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Wagga Wagga CMM 2016

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Charles Sturt University, Boorooma Street, North Wagga, Wagga Wagga, NSW
Anton Tadich (Australian Synchrotron)
Description

The Australian Synchrotron is proud to host the 40th Annual Condensed Matter and Materials Meeting in Wagga Wagga. The meeting will be held across four days, on 2 - 5 February 2016, at the Wagga Wagga campus of Charles Sturt University.

Wagga 2016 brings together the condensed matter community across the country and New Zealand, and we are pleased to welcome speakers and delegates from each state and territory as well as New Zealand. Once again this meeting will showcase the best research from around the area, and update the community on the latest techniques and application developments.

 

 

summary
Participants
  • Abdullah Alsubaie
  • Alastair Stacey
  • Andrew Squires
  • Anton Stampfl
  • Anton Tadich
  • Avijit Biswal
  • Chin-Wei Wang
  • Chris Ridley
  • Chris Woodall
  • Chun-Ming Wu
  • Claudio Cazorla
  • Clemens Ulrich
  • Colin Bleasdale
  • Craig Marshall
  • Damian Laird
  • Damian Myers
  • Daniel Jeremy Wilson
  • Daniel Sando
  • David Hoxley
  • Dmitry Miserev
  • Dominique Appadoo
  • Dongchen Qi
  • Dongyi Zhou
  • Edward Obbard
  • Eliot Gann
  • Emily Wern Jien Yap
  • Faizun Nesa
  • Fenfen Chang
  • Francesca Iacopi
  • Frederick Marlton
  • Gail Iles
  • Garry McIntyre
  • Glen Fletcher
  • Glen Stewart
  • Guochu Deng
  • Hao ZHANG
  • Harley Scammell
  • Heiko Timmers
  • Helen Brand
  • Helen Maynard-Casely
  • Hud Wahab
  • Huda Alkhaldi
  • Hyung-Been Kang
  • Irina Kondyurina
  • JAAN OITMAA
  • Jacob Evans
  • Jarrod Colla
  • Jeffrey Sellar
  • Jennifer MacLeod
  • Jerikho Bulanadi
  • Jessie Posar
  • Jim Williams
  • Jingliang Li
  • Jingyu Chen
  • John Cashion
  • John Daniels
  • John Mabon
  • John Thornton
  • Jonathan Avaro
  • Josie Auckett
  • Junda Li
  • Kay Song
  • Ken Van't Schip
  • Kirrily Rule
  • Klaus-Dieter Liss
  • Lijun Wang
  • Liu Guangqing
  • Manickam Minakshi
  • Manuel Hinterstein
  • Maryam Barmi
  • Masrur Morshed Nahid
  • Matt Woolley
  • Matthew Sanderson
  • Matthew Tate
  • Matthew Zonneveldt
  • Michael Cortie
  • Michael James
  • Mohamad Hassan Amin
  • Mohammad Jahangir Hossain
  • Muhammad Salman Maqbool
  • Nagarajan Valanoor
  • Nancy Elewa
  • Nastaran Faraji Ouch Hesar
  • Neamul Hayet Khansur
  • Nicola Barrie
  • Norman Booth
  • Nunzio Motta
  • Oleg Sushkov
  • Patrick Tung
  • Paul Graham
  • Qingyong Ren
  • Rafael Santos
  • Resta Susilo
  • Reyner White
  • Samuel Bladwell
  • Scarlet Kong
  • Scott Gleason
  • Sean Cadogan
  • Shaymaa Albohani
  • Sima Kashi
  • Simon Clark
  • Solmaz Jahangir
  • Songbai Hu
  • Stephen Collocott
  • STEWART CAMPBELL
  • Sukriti Mantri
  • Tadahiko Hirai
  • Taka Kaneko
  • Tapio Simula
  • Tilo Soehnel
  • Trevor Finlayson
  • Wayne Hutchison
  • xiaodong yuan
  • Xinzhi Liu
  • Xiquan Cheng
  • Yaroslav Kharkov
  • Zhan Sui
  • Zhigang Chen
  • Tuesday, 2 February
    • 16:00 → 18:00
      Registration and Welcome Reception
    • 18:00 → 19:30
      Dinner 1h 30m
  • Wednesday, 3 February
    • 07:30 → 08:45
      Breakfast 1h 15m
    • 08:45 → 09:00
      Opening
    • 09:00 → 09:30
      Invited talk: WM1
      • 09:00
        Pluto: the next frontier for studies of condensed matter 30m
        In July this year, the NASA New Horizons spacecraft completed an historic flyby of the Plutonian system, the first spacecraft to visit Pluto. The long-awaited data from this mission will take months to be returned in full to Earth. However, the wealth of data received so far, although small in volume, is already providing amazing insights into the surface morphology and geochemistry of Pluto and providing important clues into the inner workings of this dwarf planet. New Horizons is equipped with high resolution imaging cameras as well as geochemical equipment to investigate surface and atmospheric compositions. Using a combination of geological mapping, geochemical data and other physical measurements, planetary scientists aim to determine the processes that shape the interior and surface of Pluto and other outer solar system objects. In situ studies of the materials found on bodies within the outer solar system is an emerging area, both for planetary science and for research in Australia. The conditions of the icy satellites are simulated while data, typically diffraction, (X-ray or neutron), or IR data, is recorded. The observations and material properties obtained in these studies can then be used as a comparison to spacecraft data or an input to models of geological processes. This contribution will include a background introduction to the New Horizons mission, an overview of the findings and data so far, and a discussion of how structural condensed matter studies, particularly synchrotron and neutron studies, can unlock the processes that govern the outer solar system.
        Speaker: Dr Helen Brand (Australian Synchrotron.)
    • 09:30 → 10:00
      Contributed talk: WM2 - 3
      • 09:30
        The Australian Synchrotron in 2015 – Turning Bright Ideas into Brilliant Outcomes 15m
        When VIP visitors come to the Australian Synchrotron (Commonwealth Ministers & their minders, Directors of national and international laboratories & research institutes; VCs & DVCRs; my Mother-in-Law;…) we like to play a little game to try and impress them and to demonstrate the impact of our efforts. It goes a little like this: Mike: “Pick a topic, any topic, and I will tell you how we make a difference to that, by research carried-out at the Australian Synchrotron”. (It helps a little if they have an interest in a specific disease or medical condition, but this is not essential). VIP: “Well…, How about…”. And so on... A strange way to try and achieve the much-needed financial security that our facility so needs I hear you say; and yes, when we face some of our more imaginative foes, the link to their topic can be more than a little tenuous. (Ok sometimes, we crash and burn). However, for the most part, with about 1000 experiments per year to choose from, we walk away with our heads held high. My talk will give a brief overview of the Australian Synchrotron, as well as its status and future as one of the most substantial pieces of research infrastructure in the country. I will present some recent research highlights, particularly pertaining to condensed matter research, and challenge you to challenge us to see how the Australian Synchrotron can make a difference to your research. Pick a topic, any topic…
        Speaker: Prof. Michael James (Australian Synchrotron)
      • 09:45
        Microsecond-resolved insights by SAXS and WAXS into the early stages of CdS quantum dot formation 15m
        Semiconducting nanoparticles (quantum dots) show a wide range of potential applications due to their unique size-dependent physical and chemical properties. A major issue today concerns the make of such particles with a sufficient control of the particle size, shape and polydispersity, which calls for a good understanding of the formation mechanisms involved. We have developed a free liquid jet setup which allows to access a so far unexplored time regime from 20 µs up to 10 ms. The key advantages compared to capillary based outfits are: 1) access of very early stages (1000 times faster than in stopped-flow experiments), 2) high time resolution (down to 10 µs), 3) no radiation damage in the sample, and 4) high quality data evaluation because of missing container scattering. For longer timescales we have pioneered a free drop setup, which again provides for container-free measurements for reaction times beyond 100 ms. By SAXS experiments the sizes and morphology of the early particle states are accessible while simultaneously acquired WAXS patterns give insights into the evolution of the crystalline structure. Both SAXS and WAXS studies show, that the CdS quantum dot formation from aqueous solutions is along a non-classical two-step nucleation pathway starting with the formation of primary clusters driven by the fast ion diffusion. Further growth is by cluster attachment where the diffusion of the primary clusters appears as the growth-limiting factor. Temperature dependent data yield a diffusion with an activation energy of Eg=0.6 eV.
        Speaker: Prof. Andreas Magerl (University Erlangen-Nürnberg)
    • 10:00 → 10:30
      Invited talk: WM4
      • 10:00
        Crystalline self-stratification in polymer thin films 30m
        The orientation of molecules within thin films is of critical importance to the emerging field of organic electronics. Particularly in the case of solution processable polymers and small molecules, where alkyl side chains, included for solubility, impede conduction along that molecular direction, understanding and controlling the molecular orientation both at surfaces and in the bulk of thin films is increasingly important to further increase electronic performance. Grazing Incidence Wide Angle X-ray Scattering has been widely used to look at the orientation of crystallites within films, but a capability which has not been widely used is its potential to characterize the depth within films at which different kinds of molecular stacking occur. Using very fine control over the angle of incidence of the X-ray beam, we observe a distinct segregation of edge-on crystallinity in a film of the polymer PNDI-SVS which otherwise stacks in a highly face-on orientation. Using simulations of the X-ray Electric Field Intensity within the film, the angular variation of scattering intensity can be matched, resulting in the conclusion that the surface region extends 9 nm into the 72 nm film. During the spin-coating deposition process, a face-on orientation is initially observed, likely the result of preaggregation in solution in combination with a relatively fast-drying solvent. The stratified morphology is produced by annealing the film for a brief time, while upon further annealing, the bulk of the film eventually reorients to become edge-on, suggesting that the stratification is a non-equilibrium, kinetically-trapped state. With brief annealing, only the surface region of the film has time to reorient to the ultimately lower energy edge-on orientation. The time and temperature of this reorganization can reveal the difference in energetics at different depths within the film, illustrating how grazing incidence scattering can open up the possibility of examining thin films in novel and important ways.
        Speaker: Eliot Gann (Australian Synchrotron)
    • 10:30 → 11:00
      Morning tea 30m
    • 11:00 → 11:30
      Invited talk: WN1
      • 11:00
        Quantitative Femtosecond Charge Transfer Dynamics at Organic/Electrode Interfaces Studied by Core-Hole Clock Spectroscopy 30m
        Organic semiconductors have important applications in organic electronics and other novel hybrid devices. In these devices, the transport of charge carriers across the interfaces between organic molecules and electrodes plays an important role in determining the device performance. Charge transfer dynamics at these interfaces usually occurs at the several femtoseconds timescale which presents tremendous challenges to conventional pumb-probe based time-resolved techniques. In this talk, I will introduce our recent work in the application of synchrotron-based core-hole clock (CHC) spectroscopy on the quantitative characterisation of charge transfer dynamics in several model organic/electrode systems. The CHC technique allows us to quantify the interfacial charge transfer times with element and site/orbital specificity. Combined with other soft x-ray spectroscopies, it enables us to identify a few critical factors affecting the charge transfer dynamics at organic/electrode interfaces. **Reference** L. Cao, X.-Y. Gao, A. T. S. Wee, and D.-C. Qi, *Adv. Mater.* **26**, 7880 (2014).
        Speaker: Dr Dongchen Qi (Department of Chemistry and Physics, LIMS, La Trobe University)
    • 11:30 → 12:30
      Contributed talk: WN2 - 3
      • 11:30
        Reactions of dihalogenated 3,4-ethylenedioxythiophenes on metal surfaces 15m
        Conducting polymers are a key component of modern technologies: they are used in batteries and in displays, and they have a promising future in solar conversion and emerging technologies like flexible electronics. The polymer formed from 3,4-ethylenedioxythiophene, known as poly-3,4-ethylenedioxythiophene or PEDOT, is used in a variety of applications, primarily because of its low bandgap, transparency and stability. PEDOT is typically solution processed, and although this technique is simple, it offers limited control over the structure of the polymer. Surface-confined polymerization is emerging as an important technique for the structurally-controlled synthesis of materials like PEDOT.[1,2] In order to explore possibilities for the surface-confined synthesis of structurally well-defined PEDOT, we have studied the reactions of dibromoEDOT and dichloroEDOT on Cu(111), Ag(111) and Au(111). The function of these surfaces is twofold: they provide an ordered template for epitaxial growth, and they act as catalyst for the Ullmann dehalogenation of the precursor molecules. X-ray photoelectron spectroscopy (XPS) measurements were performed at the SXR beamline of the Australian Synchrotron to benchmark the reaction temperatures for the successive steps in the on-surface reaction for both molecules on all three surfaces. Angle-resolved near-edge x-ray absorption fine structure (NEXAFS) spectra complement the information provided by XPS, and provide insight into the molecular adsorption geometry throughout the reaction pathway. Together, these data elucidate the benefits and drawbacks of different metal surfaces and different halogens in the context of the surface-confined synthesis of ordered PEDOT. [1] M. El Garah, J.M. MacLeod and F Rosei, Surf. Sci. 613, 6-14 (2013) [2] J.A. Lipton-Duffin et al., Proc. Nat. Acad. Sci. 107 (25), 11200-11204 (2010)
        Speaker: Dr Jennifer MacLeod (QUT)
      • 11:45
        Vacancy-mediated electrical conductivity in lithium fluoride upon moderate heating 15m
        The challenge posed by charge accumulation at the interfaces of low dimensional electronic devices has resulted in a wide range of novel architectures as well as potential applications in organic electronics such as organic photovoltaics. These devices include, among others, organic light-emitting diodes and organic thin-film transistors. Within such devices, the use of lithium fluoride (LiF) as an inter-facial layer reduces the potential barrier at the interface which facilitates the efficient collection of photo-generated charge with minimal energy [1]. This manifests itself in minimising the band bending at interfaces of such devices and is attributed to the low work function of LiF, which reduces the effective work function at the interface [2] and in turn leads to efficient charge extraction/injection in the organic layer [3]. Thus the electrical properties of LiF are a subject of interest. While most alkali halides have been extensively investigated, LiF is an exception which, to date, has not been given enough attention. We show that lithium fluoride conducts electricity on heating to temperatures well below its melting point. By examining the variation in conductivity with heating along (111) plane, we show that the conductivity is due to a mechanism of ion hopping and vacancy migration through the host lattice sites. By fitting the data into the Nernst-Einstein relation the two linear regions were obtained from which upon extrapolation the activation energies for ion hopping were found to be 0.67 eV and 0.35 eV for high-temperature (region I) and low-temperature (region II) regions respectively as shown in the figure below. Conductivity of LiF has implications for its use as an inter-facial layer in photovoltaic device design and potential use in bio-sensing devices due to its cell tissue effective mass equivalence. ![LiF conductivity plot][1] [1] F. Zhu, B. Low, K. Zhang, S. Chua, Applied Physics Letters 79 (2001) 1205-1207. [2] R. Schlaf, B. Parkinson, P. Lee, K. Nebesny, G. Jabbour, B. Kippelen, N. Peyghambarian, N. Armstrong, Journal of Applied Physics 84 (1998) 6729-6736. [3] K. G. Lim, M. R. Choi, J. H. Kim, D. H. Kim, G. H. Jung, Y. Park, J. L. Lee, T. W. Lee, ChemSusChem 7 (2014) 1125-1132. [1]: https://pbs.twimg.com/media/CUNYEP_UcAAYjG8.png:large
        Speaker: Dr David Hoxley (La Trobe University)
      • 12:00
        Unconventional Molecular Weight Dependence of Charge Transport in a High Mobility n-type Semiconducting Polymer 15m
        Semiconducting polymers are of interest for a range of applications including organic light-emitting diodes (OLEDs), polymer solar cells and flexible electronics. When used as the active layer in solution-processed organic field-effect transistors (OFETs) one usually finds that charge carrier mobility increases with increasing molecular weight, due to the ability of longer chains to bridge regions of local order. Here an unconventional molecular weight dependence of charge transport is reported in n-channel OFETs based on the semiconducting polymer poly{[ N , N ′-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5′-(2,2′-bithiophene)}, **P(NDI2OD-T2)**. Five different molecular weights have been studied (10 kDa, 17 kDa, 30 kDa, 35 kDa and 41 kDa) with the charge carrier mobility in top gate bottom contact (TGBC) OFETs found to systematically increase with decreasing molecular weight. To understand the origin of this effect, the aggregating behaviour of polymer chains in solution has been studied, as well as the thin-film microstructure. From optical absorption measurements, which are sensitive to the polymer chain conformation, it is found that low molecular weight chains have an open coil conformation while higher molecular weight chains adopt a collapsed, or aggregated conformation. Analysis of Atomic Force Microscopy (AFM) measurements suggest a higher degree of polymer chain alignment in low molecular weight samples. Near Edge X-Ray Absorption Fine Structure (NEXAFS) spectroscopy measurements have also been performed that show a similar molecular orientation (backbone tilt) at the surface for all the molecular weight samples. Taken together, these results indicate that upon solution processing, the lower molecular weight samples are able to form more chain-extended thin-film morphologies that promote charge transport than the higher molecular weight samples that self-aggregate in solution produces less favorable morphologies.
        Speaker: Mr Masrur Morshed Nahid (Monash University)
      • 12:15
        An Approach to Degradation Mechanisms using Numerical Model Fitting in Thermally Activated Delayed Fluorescence (TADF) Organic Light Emitting Diodes (OLEDs) 15m
        We approach degradation mechanisms in green thermally activated delayed fluorescence (TADF) organic light emitting diodes (OLEDs) by a numerical model fitting method included a Schottky numerical model to evaluate barrier height of carrier injection at interfaces. Using temperature dependent current-voltage (I-V) behavior of hole only (HOD) device ; glass / ITO (100nm) / HAT-CN (10) / Tris-PCz (70nm) / Al (100nm) , electron only device (EOD) ; glass / ITO (100nm) / Bpy-TP2 (40nm) /LiF (0.8nm) / Al (100nm) and our model, we have obtained values for the Richardson factor, and the barrier height. From the temperature dependent I-V characteristics of the HOD and our model fitting, we have estimated PhiB(H)=0.370 [eV], A*(H)=1.0×10-2 [A/cm2/K2] and threshold voltage VTH(H)=1.5 [V] for the injection of hole carriers. Notably, the A* value of the ITO/HAT-CN/Tris-PCz interface is much smaller than that of a metal/Si interface 20). This suggests that A* is strongly dependent on the combination of ma-terials and its interface condition. Likewise, we also obtained the device parameters for the electron injection interface from the temperature dependent I-V characteristics of the EOD. From the measurement data and our model fitting, we have estimated PhiB(E)=0.285 [eV], A*(E)= 1.0×10-3 [A/cm2/K2] and VTH(E)=2.2 [V]. Therefore, we tried stress tests using 1 hour 500mA/cm2 current stress for HOD and EOD. The param-eter determined for the HOD show no significant change. In contrast to this the EOD parameters show significant change after current stressing; PhiB(E)=0.285 -> 0.345 [eV], A*(E)= 1.0×10-3 -> 1.0×10-2 [A/cm2/K2] and VTH(E)=2.2 -> 2.5 [V]. It is apparent that the interface of electron injection side has undergone significant degradation during the current stressing as revealed by the change in the device parameters. Hence, we have obtained the delayed response of luminescence under pulsed operation of delta-doped green TADF OLEDs ; glass / ITO (100nm) / HAT-CN (10) / Tris-PCz (30nm) / mCP:4CZIPN (15%,30nm) / T2T (10nm) / Bpy-TP2 (40nm) / LiF (0.8nm) / Al (100nm) after current stress. In order to approach degradation mechanisms, we fabricated a half doped structure in the emission layer. The results of pulsed operation indicate the quick response of luminescence has been generated in a very thin region con-tacted to the electron injection side in the emission layer. On the other hand, STEM cross sectional images of the TADF green OLEDs show a different contrast at interface region of Bpy-TP2 as electron injection layer between before and after the current stress. The results are consistent with changes of parameters in the EOD after current stress. From our experimental and model fitting results, we describe a degradation model dominated at electron injection interface in TADF green OLEDs.
        Speaker: Dr Tadahiko Hirai (CSIRO)
    • 12:30 → 14:00
      Lunch 1h 30m
    • 14:00 → 14:30
      Invited talk: WA1
      • 14:00
        Engineering the Diamond Surface for Quantum Technologies 30m
        Quantum technologies promise exciting and transformative futures in many areas of human endeavour. An example is the field of bio-sensing, where quantum probes are already being used to answer fundamental questions about living cells. In these applications diamond often takes centre stage, as a material which simultaneously exhibits both bio-friendly and quantum-friendly properties. This presentation will review efforts to exploit diamond for quantum bio-sensing applications, encompassing practical cellular measurements to the development of fundamentally new sensing techniques. In particular, I will address the biggest materials challenge we currently face, which is the presence of uncontrolled defects at the solid state surface, and detail the use of surface science techniques, based at the Australian Synchrotron, to understand and re-engineer this important quantum/life interface.
        Speaker: Dr Alastair Stacey (Centre of Excellence for Quantum Computation and Communication Technology, The University of Melbourne)
    • 14:30 → 15:00
      Contributed talk: WA2-3
      • 14:30
        Solvent restructuring at colloidal nanoparticle surfaces 15m
        Interfaces are the key to understand manifold chemical and physical processes, for instance catalytic reactions as well as nanoparticle nucleation and growth. Nanoparticle surfaces have a strong tendency to restructure to strained atomic arrangements in order to stabilize themselves at their finite size [1,2]. But also restructuring of the solvent molecules takes place. The presence of colloidal nanoparticles in bulk solvents induces a reorientation of the solvent molecules and a change of the hydrogen bond network in the vicinity of the particle surface. We could for the first time experimentally prove the universality of solvent restructuring around nanoparticles for a matrix of redispersed nanoparticles (ZnO, TiO2, ZrO2, Ag) in the primary alcohols methanol to 1-propanol as well as in nonpolar hexane and water. We carried out high-energy x-ray scattering experiments on colloidal dispersions with a metal ion concentration of ca. 0.4 wt% / 30 mM. We observe primarily the reorientation of solvent molecules along the surface normal, yielding a sinusoidal oscillation of the solvent electron density profile in the corresponding pair distribution functions (PDF). The rearrangement of molecules reaches out as far as 2 nm into the bulk liquid and the decays exponentially [3]. Molecular dynamics modelling predict that the solvent restructuring is influenced by the particle size, shape, crystallinity or the facetting [4]. Nucleation and growth depend on the attachment of new primary building blocks like ions or precursor clusters to existing particle surfaces. This process is determined by the interaction of the building blocks with the surface. The interaction and the electric field of the nanoparticle is however modulated by the solvent layering at the surface. We carried out in-situ PDF experiments on the nucleation of 3 nm large ZnO nanoparticles from precursor clusters in ethanol and revealed that the layering of the solvent molecules at the nanoparticle surface changes during nucleation. Understanding these changes will help us in the future to better model nanoparticle nucleation and growth. [1] Zhang, H., et al. Nature 424 (2003), 1025 [2] Gilbert, B., et al. Science 305 (2004), 651 [3] Zobel, M., et al. Science 347 (2015), 292 [4] Spagnoli, D., et al. Geochimica et Cosmochimica Acta 73 (2009) 4023 [5] Silvera Batista, C. A., et al. Science 350 (2015), 6257
        Speaker: Ms Mirijam Zobel (Friedrich-Alexander-University Erlangen-Nürnberg)
      • 14:45
        One-step synthesis of n-type Mg$_2$Ge 15m
        Magnesium-based thermoelectric materials (Mg$_2$X, X = Si, Sn, Ge) have received considerable attention due to their availability, low toxicity and reasonably good thermoelectric performance. However, the synthesis of these materials with high purity is challenging due to the volatility and high vapor pressure of magnesium. In the current study, single phase *n*-type Mg$_2$Ge has been fabricated through the one-step reaction of elemental Ge and MgH$_2$ using spark plasma sintering (SPS). This technique was used previously on the synthesis of high purity nanocrystalline Mg$_2$Si as an alternative to melting procedures, believed to reduce the formation of oxides due to the liberation of hydrogen. X-ray diffraction (XRD) analysis of fabricated bulk samples shows single phase Mg$_2$Ge. Scanning electron microscopy (SEM) analysis equipped with energy-dispersive X-ray spectroscopy (EDS) indicates that the final composition has Mg deficiency, even when excess Mg of the stoichiometry is added to the starting materials. Previous reports highlighted the effect of non-stoichiometric amounts of Mg on the thermoelectric properties of Mg-based alloys, especially in *n*-type compounds where Mg vacancies act as electron acceptors and severely reduce the efficiency of dopants. Thermoelectric properties measurements show that intrinsic Mg$_2$Ge exhibits *n*-type behavior. This work investigates the efficiency of Bi as dopant for one-step fabrication of *n*-type Mg$_2$Ge to improve its thermoelectric performance. Bismuth doping results in a significant reduction of electrical resistivity while the compound remains *n*-type, proving Bi as an electron donor in Mg$_2$Ge, as suggested by theoretical studies. However, the impact of Bi-doping on the thermoelectric properties of Mg$_2$Ge is much smaller than predicted values. Detailed microscopy analysis revealed the formation of Bi-rich precipitates at the grain boundaries of the Mg-deficient Mg$_2$Ge matrix, indicating very limited solubility of Bi in this compound. It suggests low efficiency of Bi as an *n*-type dopant for Mg$_2$Ge.
        Speaker: Mr Rafael Santos (Australian Institute of Innovative Materials (AIIM), University of Wollongong)
    • 15:00 → 15:30
      Invited talk: WA4
      • 15:00
        Towards Realisation of High-Performance Thermoelectrics for Energy Conversion 30m
        Thermoelectric materials directly convert thermal energy into electrical energy, offering a green and sustainable alternative for the global energy market.[1, 2] So far, extensive investigations have been made to improve the thermoelectric efficiency, which governed by the dimensionless figure-of-merit ZT ( ), where σ is the electrical conductivity, S is the Seebeck coefficient, T is the absolute temperature, and  is the total thermal conductivity which is the sum of the contributions from its electron (e) and lattice (L) components. Here, we developed cost-effective, and low-toxic thermoelectrics for high-efficiency energy conversion using novel industry-level approach, coupled with nanostructure and band engineering strategies. Through effective design of thermoelectric materials with engineered chemistry and unique structure, and advanced manufacturing, high-performance thermoelectrics, such as Cu2Se,[3] Bi2Se3,[4] Bi2Te3,[5-8] In3Se4,[9, 10] etc., have been realised in our group. Such innovative technology can be used for harvesting electricity from waste heat or sun light. References [1] Z.-G. Chen, G. Han, L. Yang, et al., Prog. Nat. Sci. 2012, 22, 535. [2] G. Han, Z.-G. Chen, J. Drennan, et al., Small 2014, 10, 2747. [3] L. Yang, Z.-G. Chen, G. Han, et al., Nano Energy 2015, 16, 367. [4] M. Hong, Z.-G. Chen, L. Yang, et al., Adv. Elect. Mater. 2015, 1, 201500025. [5] G. Han, Z.-G. Chen, L. Yang, et al., Acs Appl. Mater. Inter. 2015, 7, 989. [6] L. Cheng, Z.-G. Chen, L. Yang, et al., J. Phy. Chem. C 2013, 117, 12458. [7] L. Yang, Z.-G. Chen, M. Hong, et al., ACS Appl. Mater. Inter. 2015, 7, 23694. [8] L. Cheng, Z.-G. Chen, S. Ma, et al., J. Am. Chem. Soc. 2012, 134, 18920. [9] G. Han, Z.-G. Chen, L. Yang, et al., Cryst. Growth & Design 2013, 13, 5092. [10] G. Han, Z.-G. Chen, C. Sun, et al., CrystEngComm 2014, 16, 393.
        Speaker: Dr Zhigang Chen (the University of Queensland)
    • 15:30 → 16:00
      Poster Slam
    • 16:00 → 18:00
      Poster Session: Poster Session 1 and Afternoon Tea
    • 18:30 → 22:00
      Conference Dinner 3h 30m
  • Thursday, 4 February
    • 07:30 → 08:45
      Breakfast 1h 15m
    • 08:45 → 09:15
      Invited talk: TM1
      • 08:45
        The endless possibilities of graphene on heteroepitaxial silicon carbide 30m
        Epitaxial graphene grown using solid source carbon from silicon carbide wafers has been for long time the only route to obtain high quality graphene directly grown at the wafer –level, which is crucial to realise the promise of graphene for nanodevices. Nonetheless, the capability of obtaining comparable quality of graphene on silicon as opposed to silicon carbide wafers, would open an immense opportunity for graphene in integrated circuits and micro-systems in general. While encouraging results have been obtained through thermal decomposition of heteroepitaxial SiC films on silicon wafers, this has usually been limited to small areas and to the use of Si (111) surfaces. Moreover, the obtained graphene quality tends to be strongly hampered by the upper limitation in synthesis temperature set by the melting temperature of silicon. We have recently demonstrated for the first time that most of those limitations can be overcome with the use of heteroepitaxial silicon carbide films in combination with a catalytic alloy of nickel and copper. With this approach we obtain 2 layers graphene on silicon carbide with uniform coverage over the silicon wafer and an average ID/IG ratio of about 0.2 +/- 0.05 [1], indicating a substantial improvement as compared to a ratio of ~1 and above of graphene through the more conventional thermal decomposition. This novel catalytic approach on silicon holds high promise for integrated applications also through the capability for straightforward graphene micropatterning through self-aligned synthesis on pre-structured silicon carbide on silicon [2]. Moreover, we have demonstrated the potential for this approach to fabricate high –performing electrodes for integrated supercapacitor structures [3]. [1] F.Iacopi, N.Mishra, B.V.Cunning, D.Goding, S.Dimitrijev, R.Brock, R.H.Dauskardt, B.Wood and J.J.Boeckl, “A catalytic alloy approach for highly uniform graphene on epitaxial SiC on silicon wafers”, J.Mater.Res.30(5), 609-616, 2015. [2] B.V.Cunning, M.Ahmed, N.Mishra, A.R.Kermany, B.Wood, F.Iacopi, “Graphitized silicon carbide microbeams on silicon: wafer-level, self -aligned graphene on silicon wafers”, Nanotechnology 25, 325301, 2014. [3] M.Ahmed, M.Khawaja, M.Notarianni, B.Wang, D.Goding, B.Gupta, J.J. Boeckl, A.Takshi, N.Motta, S.E.Saddow, F.Iacopi, “A thin film approach for SiC–derived graphene as an on-chip electrode for supercapacitors”, Nanotechnology 26, 434005, 2015.
        Speaker: Prof. Francesca Iacopi (Griffith University, Queensland Micro and Nanotechnology Centre)
    • 09:15 → 10:45
      Contributed talk: TM2 - 6
      • 09:15
        Capturing the transition from 3C SiC(111) to graphene by XPS and STM in Ultra High Vacuum 15m
        By using X-Ray Photoelectron Spectroscopy and Scanning Tunneling Microscopy we have been able to follow the time evolution of graphene layers obtained by annealing 3C SiC(111)/Si(111) crystals at different temperatures. Analysis of the atomic resolution images and of the Carbon signal provides a clear picture of the graphene formation. We have been able to visualise by STM the first steps of graphene formation on the surface of SiC finding the sequence of reconstructions which lead from the SiC(111) surface to graphene, caused by the Si sublimation. We followed by XPS the evolution of the graphene thickness at different temperatures as a function of the annealing time, finding a power growth law with exponent 0.5. We show that a kinetic model, based on a bottom-up growth mechanism, provides a full explanation to the evolution of the graphene thickness as a function of time, allowing to calculate the effective activation energy of the process and the energy barriers, in excellent agreement with previous theoretical results. Our study provides a complete and exhaustive picture of the Si out-diffusion from SiC, establishing the conditions for a perfect control of the graphene growth by SI sublimation. ## References ## 1. Gupta, B., M. Notarianni, N. Mishra, M. Shafiei, F. Iacopi, and N. Motta, Evolution of epitaxial graphene layers on 3C SiC/Si (111) as a function of annealing temperature in UHV. Carbon, 2014. 68: p. 563-572. 2. Gupta, B., E. Placidi, C. Hogan, N. Mishra, F. Iacopi, and N. Motta, The transition from 3C SiC(111) to graphene captured by Ultra High Vacuum Scanning Tunneling Microscopy. Carbon, 2015. 91(0): p. 378-385.
        Speaker: Prof. Nunzio Motta (Queensland University of Technology)
      • 09:30
        NEXAFS characterisation of CVD graphene on copper 15m
        Technology development and device-design based upon graphene materials require reliable techniques for mass production that are time-robust and reproducible. CVD-synthesis is expected to be the prime candidate for such up-scaling. Copper is a preferred substrate for CVD. Details of the graphene-copper substrate interactions in regard to mechanical stability and electronic band structure are therefore crucial input for future device engineering. Such application will require that the electronic band-structure of different graphene materials is measured in detail and that graphene-substrate interactions are well understood. Both, the degree of sp2-hybridisation and the electronic band-structure can be directly probed with NEXAFS. The spectroscopy technique enables detailed studies of structural changes at the graphene surface and at its substrate interface. Our NEXAFS studies at the Australian Synchrotron have produced new evidence for a contentious state in graphene near 288 eV. This resonance has been intermittently observed before by others and it is often referred to as an 'interlayer state' due to a perceived analogy with graphite [1-5] . Our results for CVD-graphene synthesized on copper show a pronounced anisotropy for this state. We derive an excitation energy of 288.3 eV and a partial overlap with an isotropic contaminating resonance. After annealing and keeping the graphene in ultra-high vacuum, the NEXAFS signature of the 288.3 eV state only gradually appears and builds-up over several hours. This signature can be removed again by renewed annealing. The reversible phenomenon may thus relate to residual lattice mismatch between the graphene and the copper substrate. Associated stress may gradually be relaxed through the rippling of the graphene layer [6]. Tilting angles of >20° appear possible. The rippling is evidenced in our data by a correlated, reversible non-linearity of the cos-square-theta-dependence of the 285 eV π* resonance of graphene. References [1] Fischer et al., Phys. Rev. B, 44 (1991) 1427-1429 [2] Pacile et al., Phys. Rev. Lett., 101 (2008) 066806 [3] Jeong et al.; Phys. Rev. Lett., 102 (2009) 099701 [4] Lee et al.; J. of Phys. Chem. Lett. 1 (2010) 1247-1253 [5] Schultz et al.; Nature Communications, 2 (2011) 372 [6] Paronyan et al., ACS Nano, Vol. 5, 12, 2011, 9619
        Speaker: Mr Hud Wahab (UNSW Canberra)
      • 09:45
        Graphene Nanoplatelet Biodegradable Nanocomposites: A Comparative Study 15m
        With excellent characteristics such as high mechanical properties and electrical conductivity, graphene nanoplatelets (GNPs) can be used for reinforcing polymers and developing novel materials. In the current study, different concentrations of GNPs (0-15 wt%) were embedded into poly lactide and poly (butylene adipate-co-terephthalate) which are among the leading biodegradable polymers. Morphology of the nanocomposites was studied via scanning electron microscopy and X-Ray diffraction. Effect of GNP loading on electrical conductivity and thermal stability of the two matrices were determined. Results showed significant enhancement in both conductivity and thermal stability of polymers with addition of GNPs.
        Speaker: Ms Sima Kashi (School of Civil, Environmental and Chemical Engineering, RMIT University)
      • 10:00
        Quest for zero loss: the materials selection problem in plasmonics 15m
        Under specific conditions incoming light can excite a wavelike oscillatory resonance in the free electrons of a conducting material. When this oscillation propagates along a surface it is usually termed a surface plasmon polariton; when confined to a discrete nanoparticle as a standing wave it is more correctly termed a localised surface plasmon resonance (LSPR). There is currently considerable interest in 'plasmonics'- the study of both kinds of plasmon- because applications as diverse as biosensors, optical computing, rectenna arrays, and meta-materials can make use of them. The strength of the plasmon resonance that can be excited depends on the geometric shape of the structure and, most importantly, its dielectric function at the wavelength of interest. The dielectric function, in turn, depends directly upon the electronic density-of-states of the relevant material. Here we consider how the dielectric function can be optimised for a desired type of plasmon resonance by selection of a suitable material. The metallic elements Au and Ag are well known material choices for these applications, Al and Cu are also possibilities, while Na and K have very suitable dielectric functions but rather unfavourable chemical properties. There are additional possibilities offered by alloying or compound formation and we present examples drawn from our own work on the Ag-Au, Cu-Au, Al-Au, Al-Pt, Au-Ni and Cu-Zn systems [1-6] as examples of what can be achieved. The most important strategy when matching material to desired plasmon resonance is that the energy range over which interband transitions occur must, in general, be avoided. Given the manner in which the Drude and interband components of the dielectric function interact, the region just below the absorption edge energy is particularly attractive. This can be accessed by suitable selection of material or by manipulation of the geometry or dielectric environment of the nanostructure of interest. In addition to metals, however, a range of semiconducting compounds are also of interest for plasmonic applications, although generally at somewhat longer wavelengths than for the metals. The diverse possibilities offered by these compounds are assessed. References 1. K. S. B. De Silva, A. Gentle, M. Arnold, V. J. Keast & M. B. Cortie, J. Phys. D: Appl. Phys., vol.48, 2015, pp.215304. 2. V. Keast, K. Birt, C. Koch, S. Supansomboon & M. Cortie, Applied Physics Letters, vol.99, 2011, pp.111908. 3. V. J. Keast, R. L. Barnett & M. B. Cortie, J. Phys. Cond. Matter., vol.26, 2014, pp.article 305501. 4. V. J. Keast, J. Ewald, K. S. B. D. Silva, M. B. Cortie, B. Monnier, D. Cuskelly & E. H. Kisi, J. Alloys & Compounds, vol.647, 2015, pp.129-135. 5. V. J. Keast, B. Zwan, S. Supansomboon, M. B. Cortie & P. O. Å. Persson, J. Alloys Compd., vol.577, 2013, pp.581-586. 6. D. J. McPherson, S. Supansomboon, B. Zwan, V. J. Keast, D. L. Cortie, A. Gentle, A. Dowd & M. B. Cortie, Thin Sol. Films, vol.551, 2014, pp.200-204.
        Speaker: Prof. Michael Cortie (University of Technology Sydney)
      • 10:15
        Development of Hydrophilic Materials for Nanofiltration Membrane Achieving Dual Resistance to Fouling and Chlorine 15m
        A hydrophilic thin-film-composite (TFC) nanofiltration (NF) membrane has been developed through the interfacial polymerization (IP) of amino-functional polyethylene glycol (PEG) and trimesoyl chloride. The selective layer is formed on a polyethersulfone (PES) support that is characterized using FTIR, XPS and SEM, and is dependent on monomer immersion duration, and the concentration of monomers and additives. The higher hydrophilicity alongside the larger pore size of the PEG-based selective layer is the key to a high water flux of 66.0 L m-2 h-1 at 5.0 bar. With mean pore radius of 0.42 nm and narrow pore size distribution, the MgSO4 rejections of the PEG based PA TFC NF membranes can reach up to 80.2 %. The hydrophilic PEG based membranes shows positive charged since the isoelectric points range from pH=8.9 to pH=9.1 and the rejection rates for different salts of the novel membranes are in the order of R(MgCl2)>R(MgSO4)>R(NaCl)>R(Na2SO4). The pore sizes and water permeability of these membranes are tailored by varying the molecular weight and molecular architecture of amino-functional PEG. Due to the unique structure of the selective layer of the PEG based membranes consisting of saturated aliphatic construction unit (CH2-CH2-O), the membranes demonstrate dual resistance to fouling and chlorine. The membranes maintain good salt rejections and high water flux of PEG based membranes after treatment by 2000 ppm NaClO for 24 hours. Interestingly, the PEG based membranes exhibit excellent fouling resistance with a water flux recovery of 90.2 % using BSA as a model molecule. More importantly, the hydrophilic PEG based NF membranes have been exploited to separate several water soluble antibiotics (such as tobramycin, an aminoglycoside antibiotic applied in the treatment of various types of bacterial infections), showing excellent performance in concentration or removal of antibioics.
        Speaker: Dr Xi Quan Cheng (School of Chemical Engineering and Technology, State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), Harbin Institute of Technology, Harbin 150001, P.R. China;Manufacturing Flagship ,CSIRO, Private Bag 33, Clayton South MDC, VIC 3169, Australia.)
    • 10:30 → 11:00
      Morning Tea 30m
    • 11:00 → 11:30
      Invited talk: TN1
      • 11:00
        Atomic-scale understanding of CO2 adsorption processes in metal-organic framework (MOF) materials using neutron scattering and ab initio calculations 30m
        The dependence of the industrialised world on fossil-fuel energy generation technologies and consequent increase in atmospheric CO2 concentrations has been blamed for emerging adverse climate effects, including an increase in global mean temperatures [1]. Until renewable, carbon-free energy sources can be efficiently harnessed to meet the world’s energy needs, interim measures are sought to suppress the atmospheric release of CO2 from traditional coal and natural gas combustion processes. Microporous materials such as zeolites and metal-organic frameworks (MOFs) are therefore being investigated for the separation and capture of CO2 at various stages of the combustion cycle. MOFs represent one of the most promising classes of materials for this application, offering unrivalled tunability of structural and chemical characteristics via the substitution of metals and choice and functionalisation of ligands [2]. In order for a MOF to be rationally tuned for improved performance, the nature of the interactions between the host framework and guest molecules must be well-understood at the atomic level. Our research targets this detailed understanding of MOFs using neutron scattering and computational methods. We are currently investigating several MOFs which display unexpected sorption properties such as “reverse sieving” – that is, selectively absorbing larger gas molecules while rejecting smaller ones – and unusual lattice expansion effects. Using in situ diffraction to locate the preferred binding sites of guest molecules in the framework, inelastic neutron scattering to probe system dynamics, and density functional theory-based molecular dynamics simulations to validate and interpret our experimental results, we are able to gain detailed information about the mechanisms of gas uptake and diffusion in these exciting new MOF materials. [1] S. Solomon, G.K. Plattner et al., Proc. Natl. Acad. Sci. USA **106** (2009) 1704-1709. [2] G.J. Kearley & V.K. Peterson (eds.), Neutron Applications in Materials, Springer (2015).
        Speaker: Josie Auckett (ANSTO)
    • 11:30 → 12:30
      Contributed talk: TN2 - 5
      • 11:30
        Crystallographic and magnetic structure study in SrCo3-x by high resolution x-Ray and neutron powder diffraction 15m
        Transition metal oxides (TMOs) represent a wide set of materials with a broad range of functionalities, including superconductivity, magnetism, and ferroelectricity, which can be tuned by careful choice of parameters such as strain, oxygen content, and applied electric and magnetic fields [1-4]. This tunability makes TMO’s ideal candidate materials for use in developing novel information and energy technologies and SrCoO3 provides a particularly interesting system for investigation due to its propensity to form oxygen-vacancy-ordered structures as the oxygen content is decreased. The ties between structural and functional properties of this material are obvious as it undergoes simultaneousy structural and magnetic phase transitions between two topotactic phases: from a ferromagnetic perovskite phase at SrCoO3.0 to the antiferromagnetic brownmillerite SrCoO2.5 [1,5]. In this study we have determined their crystallographic and magnetic structures of SrCoO2.50, SrCoO2.75, SrCoO2.875, and cubic SrCoO3.00 using high resolution X-ray and neutron powder diffraction from 4 K to 600 K. The correct structure of oxygen-deficient end-member SrCoO2.5 was determined in space group of Imma, instead of Pnma or Ima2 proposed previously, with G-type antiferromagnetic order up to TN = 570 K. In SrCoO2.875, clear peak splitting was observed from (200) in cubic phase to (004) and (440) in tetragonal phase, indicating that the precise structure is I4/mmm with a = b = 10.829(9) Å and c = 7.684(2) Å at 95 K. the corresponding magnetic structure is ferromagnetic with 1.86(4) µB per formula, in accordance to a spin configuration of cobalt ions with an intermediate spin state of both on Co3+ and on Co4+. The end member SrCoO3.00 possesses a simple cubic crystal structure with a = 3.817(2) Å at 95 K, and ferromagnetic order up to 280 K. The magnetic moment of 1.96(8) µB /Co4+ corresponds to an intermediate spin state of Co4+. [1] H. Jeen et al., Nature Mater. 12, 1057 (2013). [2] Yang et al., Nature Mater. 8, 485 (2009). [3] J. Seidel et al., Nature Com. 3, 799 (2011). [4] T. Takeda, et al., J. Phys. Soc. Jpn. 22, 970 (1972). [5] S. J. Callori, J. Seidel, C. Ulrich et al., Phys. Rev. B 91, 140405(R) (2015).
        Speaker: Ms Fenfen Chang (The school of physics, university of New South Wales, NSW 2052)
      • 11:45
        Hydrates under pressure – new insights from sulfuric acid hydrates 15m
        Hydrates are a rich and diverse class of materials that display a wide range of structures and properties – a feature that is only exaggerated when they are subjected to high-pressures. Consequently, these have implications on our understanding of many outer solar system bodies, where hydrates are amongst the dominant materials found there. For Europa and Ganymede, two moons under intense investigation from past and future space missions, their surfaces seen to be mostly water-ice and hydrates. Despite the apparent ‘simplicity’ of these materials, we still observe very complex geological formations on these moons – including subduction [1]. Hence, we need to understand the transformations of candidate surface materials under a range of pressure/temperature conditions in order to accurately explain the formations on these icy surfaces. One hydrate candidate material for the surfaces of these moons are sulfuric acid hydrates, formed from radolytic sulfur (from Io) reacting with the surface ice. Sulfuric acid hydrates have already been established to have a complex phase diagram with composition [2]. We have now used the Mito cell [3] at the PLANET instrument [4] to undertake the first investigation of the high-pressure behavior of the water rich sulfuric acid hydrates. Compressing at 100 K and 180 K we see that the hemitriskaidekahydrate becomes the stable water-rich hydrate and observe some interesting relaxation behaviour in this material at pressure, which could have significant consequences for the interiors of Ganymede. 1. Kattenhorn, S.A. and L.M. Prockter, Evidence for subduction in the ice shell of Europa. Nature Geosci, 2014. 7(10): p. 762-767. 2. Maynard-Casely, H.E., H.E.A. Brand, and K.S. Wallwork, Phase relations between the water-rich sulfuric acid hydrates, potential markers of thermal history on Jupiter’s icy moons. Icarus, 2014. 238(0): p. 59-65. 3. Komatsu, K., et al., Development of a new P–T controlling system for neutron-scattering experiments. High Pressure Research, 2013. 33(1): p. 208-213. 4. Hattori, T., et al., Design and performance of high-pressure PLANET beamline at pulsed neutron source at J-PARC. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2015. 780(0): p. 55-67.
        Speaker: Dr Helen Maynard-Casely (Australian Nuclear Science and Technology Organisation)
      • 12:00
        Inelastic neutron scattering as a means for determining the magnetic exchange interactions in the frustrated quantum spin chain, Linarite. 15m
        One of the simplest models exhibiting one dimensional (1D) frustrated quantum interactions is the so called J1-J2 model. In this model competing ferromagnetic nearest-neighbour interactions (J1>0) and antiferromagnetic next-nearest-neighbours (J2<0) can give rise to novel phenomena such as multiferroicity for spiral spin states. Linarite, PbCuSO¬4(OH)2 is a natural mineral ideally suited to the study of frustration in J1-J2 systems due to an accessible saturation field and the availability of large single crystals well suited to neutron investigations. In this material the Cu2+ ions form spin S = 1/2 chains along the b direction with dominant nearest-neighbour FM interactions and a weaker next-nearest-neighbour AFM coupling, resulting in a magnetically frustrated topology [1, 2]. We present a neutron scattering study of linarite revealing a helical magnetic ground state structure with an incommensurate propagation vector of (0 0.186 ½) below TN = 2.8K in zero magnetic field [3]. From detailed measurements in magnetic fields up to 12 T (B || b), a very rich magnetic phase diagram will be presented. In particular we will present new inelastic neutron scattering data and compare this with theoretical modelling of the spin Hamiltonian. These theoretical calculations imply that linarite possesses an xyz exchange anisotropy. Our data establish linarite as a model compound of the frustrated one-dimensional spin chain, with ferromagnetic nearest-neighbour and antiferromagnetic next-nearest-neighbour interactions. [1] M. Baran et al., Phys. Stat. Sol. (c) 3, 220 (2006). [2] Y. Yasui, M. Sato, and I. Terasaki, J. Phys. Soc. Jpn. 80, 033707 (2011). [3] B. Willenberg et al., Phys. Rev. Lett. 108, 117202 (2012).
        Speaker: Dr Kirrily Rule (The Bragg Institute, ANSTO)
      • 12:15
        An investigation of magnetic structure and spin reorientation in Cr and Mn doped rare earth ferrites using neutron powder diffraction 15m
        Rare earth orthoferrite RFeO3 is a family of perovskite with fantastic property, such as ultra-fast spin switching[1], photomagnetic excitation[2]and multiferrocity[3]. These properties usually determined by their magnetic structure and unique spin reorientation(SR) effect. The antisymmetric interaction(DM interaction)[4] induce a weak ferromagnetism at room temperature, while the large anisotropic interaction of R3+ ion induce a rotation of Fe3+ spin in the ac or ab plane, viz. spin reorientation. Usually there are 3 types magnetic structure for orthoferrite, in terms of Bertaut’s notation[5], $\Gamma_{4}(G_xA_yFz)$, $\Gamma_2(F_xC_yG_z)$ and $\Gamma_1(A_xG_yC_z)$. For most of magnetic $R^{3+}$, there is $\Gamma_{4}(G_xA_yF_z) \rightarrow \Gamma_2(F_xC_yG_z)$ transition except $R^{3+}=Dy^{3+}$ upon cooling[6], which show a $\Gamma_{4} \rightarrow \Gamma_1$. We investigated the magnetic structure and SR transition of Cr doped $HoFeO_3$ and Mn-doped $TbFeO_3$ using neutron powder diffraction. We found Cr substitution for Fe leads to an increasing SR transition temperature of $\Gamma_4 \rightarrow \Gamma_2$ dramatically. On the other side, the Mn substitution of Fe in $TbFeO_3$ vanishes the $\Gamma_4 \rightarrow \Gamma_2$ transition while induces a novel $\Gamma_4 \rightarrow \Gamma_1 \rightarrow \Gamma_4 $ transition. This is unusual because it is usually think it is the the anisotropic rare earth ion determines the SR property. Our observation demonstrate a delicate balance of magnetic interaction in system. This will provide us new interesting physics and potential functional materials. References [1] A. V. Kimel, B. A. Ivanov, R. V. Pisarev, P. A. Usachev,A. Kirilyuk, and T. Rasing, Nat. Phys.5, 727(2009). [2]J. A. de Jong, A. V. Kimel, R. V. Pisarev, A. Kirilyuk, and T. Rasing, Phys. Rev. B 84, 104421(2011). [3]Y. Tokunaga, S. Iguchi,T. Arima and Y. Tokura, Phys.Rev.Lett.101,097205 (2008) [4]I. Dzyaloshinskii, J. Phys. Chem. Solids 4, 241 (1958); T. Moriya, Phys. Rev. 120, 91 (1960). [5]E. F. Bertaut, Magnetism, edited by G. T. Rado and H. Suhl (Academic, New York, 1963), Vol. 3, p. 149. [6]R. L. White, J. Appl. Phys. 40, 1061(1969)
        Speaker: Dr Xinzhi Liu (China Institute of Atomic Energies, Beijing, 102413, China/Bragg institute, ANSTO, 2232, NSW)
    • 12:30 → 14:00
      Lunch 1h 30m
    • 14:00 → 14:30
      Invited talk: TA1
      • 14:00
        X-radiation in health and disease: Novel approaches to the study of disease processes and therapy 30m
        Our current medical knowledge and understanding of human biology and physiology have been predicated by our capacity to image organs, body structures, different types of tissues and particular cell types. These imaging modalities range from advanced microscopy for imaging of cells and tissues through to 2D and 3D macroscopic techniques for imaging of tissues and organs. Soft tissues in particular are difficult to image, especially when surrounded by dense structures such as bone. Also, some regions, such as the brain, require special investigative techniques as they are closed tissue/organ structures with low contrast features. Medical diagnoses, monitoring of disease progression, efficacy of therapies and the recent advent of ‘targeted imaging’ rely upon techniques such as X-ray analysis, MRI, Positron Emission Tomography (PET) and more. In this seminar several recent adaptions of X-ray and synchrotron-based X-ray science will be related. In particular, Phase-contrast X-ray imaging (PCXI), also termed microfocus imaging, X-ray Fluorescence Microscopy (XFM) and Microbeam X-ray Therapy (MRT) will be discussed. Since the discovery of X-rays and development of medical X-ray sources, X-ray imaging has accounted for approximately 60% of medical diagnostic procedures; X-ray imaging is still the predominant technology used in medicine. Over the past 30 years radioisotope-based imaging has expanded substantially with 3D positron emission tomography (PET) and combined PET/MRI being developed for simultaneous structural and functional imaging. More recently, advanced 3D imaging techniques have been aligned with targeted therapies and high resolution multi-modal imaging to improve our capabilities in definition of organ boundaries and particular tumours and organ abnormalities. Microbeam radiation therapy (MRT) is another capability and this is currently being developed at the Australian Synchrotron. Synchrotrons produce a broad range of electromagnetic radiation applicable for diverse analyses such protein crystallography, X-radiation for fluorescence spectroscopy, for mapping and quantification of trace metals, and for fast X-ray tomography for structural imaging. Access to synchrotron light sources has led to a renaissance in utilisation of X-rays for diverse imaging applications and novel radiation therapies. During this seminar the importance of advanced imaging techniques and synchrotron radiation to enable investigation of a range of diseases will be related. This presentation will include specific studies in which application of synchrotron radiation has aided investigations into bone disease and bone cancers, the study of brain abnormalities including epilepsy and traumatic brain injury and targeted therapy using MRT. Advanced medical imaging techniques have been central to our understanding of disease processes and have the potential to aid clinicians when considering therapeutic interventions. The strong synergy that occurs in interdisciplinary research has been crucial to these developments. Project design and efficient implementation of advanced imaging techniques to achieve meaningful outcomes in science and medicine will also be discussed. Acknowledgement: The contribution of the many scientists and organisations involved with this work will be related during delivery of this invited seminar.
        Speaker: Prof. Damian Myers (The University of Melbourne)
    • 14:30 → 15:30
      Contributed talk: TA3 - 4
      • 14:30
        Investigation of Targeting Capabilities of Peptide-conjugated Endocannabinoid-based lipid Nanoassemblies in the Treatment of Arthritis 15m
        Nicola Barrie, Marina Ali, Nicholas Manolios, Minoo J. Moghaddam1 Dept Rheumatology, Westmead Hospital and University of Sydney; and 1Manufacturing Flagship, CSIRO, North Ryde. **Aims**: To develop a novel drug delivery system using cannabinoid amphiphiles and evaluate the synovial homing capabilities of peptide-conjugated nanoparticles for the targeted treatment of arthritic conditions. **Background:** Chronic inflammatory joint disease is a common problem that results in a great deal of pain, dysfunction and socio-economic hardship to those affected. We have developed and synthesized a series of endocannabinoid agonists that have the ability to self-assemble in the presence of a polar solvent to form a variety of nanoassembled particles governed by local constraints imposed by the effective shape of the molecule. The cannabinoid amphiphiles ability to self assemble makes them potentially useful vehicles for the encapsulation and controlled release of hydrophilic, hydrophobic and amphiphilic drugs. Furthermore, modification of pharmacokinetic properties through polymer conjugation allows the customisation and specific targeting of nanoparticles within a physiological system allowing a highly sophisticated drug delivery system. Together, the nanoparticles capacity for anti-arthritic drug deliver coupled with the targeting capability of peptides such as HAP-1, facilitates a selective accumulation of therapeutic agents in the inflamed synovium, potentially improving drug efficacy at the diseased site without compromise to healthy tissue. In addition to targeted drug delivery, the endogenous nature of cannabinoid amphiphiles further increases biocompatibility and may act in an analgesic capacity. Modulation of the endocannabinoid receptor system via interaction of amphiphiles endocannabinoid lipid constituents facilitates the potential for pain relief associated with rheumatoid arthritis via manipulation of the endocannabinoid system. **Methods**: Lipid-based amphiphile components for nanoassemblies were synthesized in large scale. HPLC, LC/MS, Polarised optical microsopy (POM) and NMR were employed to examine the bulk phase of a variety of lipid mixtures at 25°C and 37°C. The synovium targeting peptide, HAP-1, and pegylated lipids were incorportated on the surface of these nanoassemblies and its physicochemical properties assessed using POM, particle sizing, and cryo-TEM. "Did" fluorochrome was incorporated into the nanoparticles lipid membrane and its bio-distribution was imaged in normal rat models via near-infrared fluorescence imaging system (NIRF). **Results and Discussion**: Endogenous monoethanolamide lipids oleoylethanolamide (OEA) and linoleoylethanolamide (LEA) were synthesized and purified to greater than 98% purity. Both the monoethanolamide head group and the unsaturated hydrophobe are of key importance in dictating the self assembly behaviour of these molecules. The current study demonstrated the ability of endogenous fatty acid monoethanolamides with an increasing degree of hydrocarbon unsaturation to form cubic phases at 25°C and 37°C. 40% OEA/60%LEA was established as the threshold ratio for cubic stability at physiological temperatures and therefore the most physiologically relevant mixture. Functionalized 40% Oleoyl-PEG-2000 was synthesized, fluorescently tagged and either conjugated with or without HAP-1 peptide. HAP-1 conjugated nanoparticles demonstrated homing capacity, localising in the knee and hip joints in normal rats, whilst untagged nanoparticles exhibited no specific distribution.
        Speaker: Ms Nicola Barrie (CSIRO, Manufacturing)
      • 14:45
        Sodium for securing future renewable energy supply 15m
        The storage and recovery of electrical energy is widely recognized as one of the most important areas for energy research. Although renewable energy such as i.e. wind and solar generated electricity is becoming increasingly available in many countries including Australia, these sources provide only intermittent energy. Thus, energy storage systems are required for load levelling, allowing energy to be stored and used on demand. Energy storage in rechargeable batteries and supercapacitors is the most promising prospect for ensuring consistent energy supply [1-2] therefore allowing greater penetration of renewable energy into the electricity grid. Energy storage capability also has obvious benefits in terms of greenhouse emissions. Issues such as the environment, the rapid increase in fossil fuel prices, and the increased deployment of renewable energy sources, provide a greater need for the development of electrochemical energy storage, especially for large-scale applications. Thus, materials research and computational modelling play a key role in making further progress in the field of energy storage. Energy storage devices based on sodium have been considered as an alternative to traditional lithium based systems because of the natural abundance, cost effectiveness and low environmental impact of sodium. Phosphate materials such as NaNiPO4, NaMnPO4, NaCoPO4 and NaNi1/3Mn1/3Co1/3PO4 will be discussed at the conference. Sodium transition metal phosphate has served as an active electrode material for an energy storage device [3-4]. The development of sodium transition metal phosphate with special emphasis on structural changes and novel synthetic approach can underpin technological advancements in small renewable energy harvesting and power generation technologies. The characteristics of the fabricated device such as improved storage capability, cycling stability, safety and economic life - cycle cost made this an attractive alternative to conventional charge storage devices using more expensive materials. **References** 1. J. Zhang, J. Jiang, H. Li, and X. S. Zhao, Environ. Sci. 4 (2011) 4009. 2. C. Liu, F. Li, L.-P. Ma, M.-M. Cheng, Adv. Mater. 22 (2010) E28. 3. M. Minakshi, D. Meyrick and D. Appadoo, Energy & Fuels 27 (2013) 3516. 4. M. Minakshi, T. Watcharatharapong, S. Chakraborty, R. Ahuja, S. Duraisamy, P. T. Rao and N. Munichandraiah, Dalton Trans. (2015) DOI 10.1039/c5dt03394b.
        Speaker: Dr Manickam Minakshi (Murdoch University)
      • 15:00
        Bi(III)-containing lanthanum germanium apatite-type oxide ion conductors and their structure-property relationships 15m
        Oxide ion conductors are used in a wide variety of applications, including oxygen sensors and separation membranes, but are undergoing significant study for their use in solid oxide fuel cells (SOFCs), which allow for the direct conversion of chemical to electrical energy. Apatite-type silicates and germanates, La9.33+x(TO4)6O2+3x/2 (T = Si,Ge), have exhibited high oxide ion conductivities, potentially allowing for their use in SOFCs. Apatite-type compounds have the general formula, [AI4][AII6][TO4]6X2±δ, (A = alkaline or rare earth metal, or Pb; T = Ge, Si, P, V; X = O, OH, halides) and can be thought of as comprised of a framework of AI4(TO4)6 with flexible cavities containing AII6X2 units. The structures of apatite-type materials are primarily hexagonal, with the remainder being monoclinic, with several triclinic examples known. The origin of the triclinic structure is thought to be partly due to the size differences between the units comprising the framework and those within the cavities. The inclusion of interstitial oxide ions have been shown to promote the triclinic distortion, potentially caused by further expansion of the framework. Three novel Bi(III)-containing lanthanum germanium apatite compounds (Bi2La8[(GeO4)6 ]O3, Bi4Ca4La2[(VO4)2(GeO4)4]O2, and Bi4Ca2La4[(GeO4)6]O2) were synthesised by a solid state synthetic method, before undergoing AC impedance spectroscopy experiments to study their electrical properties. The Bi2La8[(GeO4)6 ]O3 compound has been identified as being the first bismuth containing apatite with a triclinic structure, whilst the Bi4-containing compounds possess hexagonal structures. All samples show high levels of conductivity, with the triclinic sample possessing higher conductivity values than the hexagonal samples at high temperature.
        Speaker: Mr Matthew Tate (Bragg Institute, ANSTO)
      • 15:15
        Low temperature effect of lithium diffusion in 18650-type MNC battery 15m
        Investigations of the phenomena in atomic scale are essential for fully understandings of the activities in battery operation. The battery is known to be operated in a broad temperature range below and above the ambient temperature. Temperature change could affect the performance, and might even raise safety issue. Li-platting, where metallic Li-ions accumulate onto the graphite anode, is a recently realized atomic pheromone that severely degrades the performance of the battery. These including capacity loss, impedance raise, activity slowing down and aging speeding up. It is now known that intercalation into the graphite and platting onto the graphite surface can both occur when Li-ions return to the graphite anode upon charging. Li-plating will partially block the insertion of Li-ions onto the graphite electrode in some extent, which reduces the migration of Li-ions during discharging and charging. Clearly, local environment, such as temperature or electric field, could affect the insertion rate, but experimental study or theoretical modeling concerning these effects are still limited. Here, we report on the results of studies made, using cold neutron triple-axis spectrometer – SIKA’s elastic mode, on the Li+ diffusion rate of an 18650-type Li-ion battery in discharging-charging operations, carried out at and below the ambient temperature. Sizable in-situ neutron diffraction intensities for the {001} reflection of LiC6, for the {002} reflection of LiC12, as well as for the {004} reflection of LiC54 were clearly detected in very 5 minute interval during a discharging-charging operation, which were then used to extract the Li+ diffusion rate during operation. Interestingly, operation with a C/5 discharging rate performed at -20 ℃ causes a dramatically 25% reduction in the Li+ diffusion rate and even more surprisingly the discharge transfers only 35% of the Li out of the graphite anode since the diffusion essentially stop in the early stage (~1/3) of the discharge period. The reduction and stopping of Li+ diffusion can effectively corrected by employing a lower discharging rate in the operation.
        Speaker: Dr Chun-Ming Wu (NSRRC)
    • 15:30 → 16:00
      Poster Slam: Poster Slam 2
    • 16:00 → 18:00
      Poster Session: Poster session 2 and Afternoon Tea
    • 18:00 → 19:30
      Dinner 1h 30m
    • 19:30 → 22:00
      Quiz
  • Friday, 5 February
    • 07:30 → 08:45
      Breakfast 1h 15m
    • 08:45 → 09:15
      Invited talk: FM1
      • 08:45
        A Morphotropic Phase Boundary in Samarium-modified Bismuth Ferrite Thin Films 30m
        Interfacial control of a polar (rhombohedral)-to-non-polar (orthorhombic) phase transition in (001) oriented epitaxial BiFeO3/(Bi1-xSmx)FeO3 superlattices is presented. We demonstrate controlling the composition at which a polar phase transformation takes place by tuning the strength of the interlayer interactions while holding the average composition constant. It is shown that the thickness of the superlattice layers have a strong influence on the interlayer polar coupling, which in turn changes the phase transition. For shortest periods studied (layers 5 and 10 nm thick) the onset of the phase transition is suppressed along with a significant broadening (as a function of Sm3+ concentration) of an incommensurately modulated phase, determined by two-dimensional x-ray diffraction mapping. Consequently, ferroelectric character with robust polarization hysteresis and enhanced dielectric constant, is observed even for substitution concentration of Sm3+ which would otherwise lead to a leaky paraelectric in single-layer (Bi1-xSmx)FeO3 films. The experimental results are fully consistent with a mean-field thermodynamic theory which reveals that the strength of the interlayer coupling is strongly affected by the polar-polar interaction across the interface. Part of this work appears in Phys. Rev. B 90, 245131(2014).
        Speaker: Nagarajan Valanoor (UNSW Australia)
    • 09:15 → 10:30
      Contributed talk: FM2 - 6
      • 09:15
        Reversible electrochromism, elasto-optic and thermo-optic effects in BiFeO3 films 15m
        Chromism refers to a change in optical absorption of a material upon application of stimulus; e.g. photochromism – light; thermochromism – heat; electrochromism – electric charge; magnetochromism – magnetic field. This phenomenon has wide applications, in for example so-called ‘smart glass’ which can be switched from a transparent to opaque state through the application of voltage, heat, or light. Bismuth ferrite (BiFeO3 – BFO) is the only known single-phase multiferroic material whose ordering temperatures are above ambient (ferroelectric TC = 1200 K; antiferromagnetic TN = 640 K) [1]. As a consequence, this material has attracted enormous research interest, on both a fundamental level and for its promise in room-temperature spintronics. In addition to its outstanding ferroelectric properties and rich spin physics, BFO has rather striking optical properties: a band gap in the visible range (attractive for light harvesting applications); a bulk photovoltaic effect with open-circuit voltages much higher than the band gap, very large birefringence, and a significant electro-optic response [2]. Epitaxial strain has been shown to be a powerful means of modifying the physical properties of BFO films [3]. By depositing strained thin films on substrates with different lattice parameters, the effects of both compressive and tensile strain can be explored. Important phenomena revealed using this technique are the drastic modification of the ferroelectric ordering temperature [4], and the spin order [5]. In addition, large compressive strains can stabilize a highly-distorted polymorph (T-like phase BFO) which shows distinctly modified physical properties when compared to the R (bulk-like) phase. Of particular relevance to this work is the larger optical band gap and the related modulation of optical absorption for photon energies near the band edge. In this presentation we first describe the effect of epitaxial strain on the optical band gap and refractive index of strained BFO films. Via strain engineering techniques we uncover a large elasto-optic effect (change in refractive index with strain) that surpasses that of the best acousto-optic materials (such as quartz or TeO2). More importantly, through dynamic switching between the different phases, we demonstrate a time-stable, reversible, and intrinsic electrochromic effect. Furthermore, through temperature dependent optical measurements, we reveal a large thermo-optic effect (change in index with temperature), a phenomenon which could be attractive for optical modulators or switches. Our results constitute an important first step in the development of integrated multifunctional thin film optical devices based on complex oxides. Indeed the coupling of optical, magnetic, and piezoelectric orders possible in this class of materials suggests new device opportunities based on ferroelectric and multiferroic thin films. References [1] G. Catalan and J.F. Scott, Adv. Mater. 21, 2463 (2009). [2] D. Sando et al, Phys Rev. B 89, 195106 (2014). [3] D. Sando et al, J. Phys. Cond. Mat. 26, 473201 (2014). [3] I.C. Infante et al, Phys. Rev. Lett. 105, 057601 (2010). [4] D. Sando et al, Nat. Mater. 12, 641 (2013).
        Speaker: Dr Daniel Sando (School of Materials Science and Engineering, University of New South Wales)
      • 09:30
        Effects of $^{18}$O isotope substitution in multiferroic $R$MnO$_3$ ($R$=Tb, Dy) 15m
        Multiferroic materials demonstrate desirable attributes for next-generation multifunctional devices as they exhibit coexisting ferroelectric and magnetic orders. In type-II multiferroics, coupling exists that allows ferroelectricity to be manipulated via magnetic order and vice versa, offering potential in high-density information storage and sensor applications. Despite extensive investigations into the subject, questions of the physics of magnetoelectric coupling in multiferroics remain, and competing theories propose different mechanisms. The aim of this investigation was to study changes in the statics and dynamics of structural, ferroelectric and magnetic orders with oxygen-18 isotope substitution to shine light into the coupling mechanism in multiferroic $R$MnO3 ($R$=Tb, Dy) systems. We have performed Raman spectroscopy on $^{16}$O and $^{18}$O-substituted TbMnO3 single crystals. Oxygen-18 isotope substitution reduces all phonon frequencies significantly. However, specific heat measurements determine no changes in Mn$^{3+}$ (28 and 41 K) magnetic phase transition temperatures. Pronounced anomalies in peak position and linewidth at the magnetic and ferroelectric phase transitions. While the anomalies at the sinusoidal magnetic phase transition (41 K) are in accordance to the theory of spin-phonon coupling, further deviations develop upon entering the ferroelectric phase (28 K). Furthermore, neutron diffraction measurements on $^{16}$O and $^{18}$O-substituted DyMnO$_{3}$ powders show structural deviations at the ferroelectric phase transition (17 K) in the order of 100 fm in the $b$ direction. The $Pbnm$ space group is centrosymmetric and therefore does not allow ferroelectricity via atomic displacements, however our Reitveld analysis for the subgroup P2$_1$ shows significant displacements and polarisation along $b$ that is comparable to the experimental value, making it the most promising candidate for ionic displacement induced polarisation in DyMnO$_{3}$. These combined results demonstrate that structure is an important consideration in the emergence of ferroelectricity in these materials.
        Speaker: Mr Paul Graham (University of New South Wales)
      • 09:45
        Growth and Properties of Strain-tuned SrCoOx (2.5≤x<3) Thin Films 15m
        Controlling material properties by strain is one of the main concepts of thin film growth technology. By altering the order parameter in ferroic materials with which the lattice is coupled, new properties can be achieved, e.g. in perovskite SrCoOx which was identified as a parent phase of strong spin-phonon coupling materials. Here, we present results on a strain-induced antiferromagnetic-ferromagnetic phase transition in high quality epitaxial SrCoOx (2.5≤x<3) (oxygen deficient SrCoO3) thin films grown on (001) SrTiO3, (110) DyScO3 and (001) LaAlO3 substrates by pulsed laser deposition. Electronic and magnetic properties of the samples were characterized by XAS, XPS, neutron scattering and magnetometry measurements. Our results demonstrate that the ferromagnetism observed in SrCoOx/SrTiO3 can be suppressed and changed to antiferromagnetism in SrCoOx/DyScO3 through tensile strain. - Further measurements on SrCoOx/LaAlO3 are currently on-going.
        Speaker: Mr Hu Songbai (UNSW Australia)
      • 10:00
        Experimental observations of grain-scale property coupling in electroceramics 15m
        Fundamental understanding of electro-mechanical properties of ceramics requires detailed multi-length-scale analysis methods. Previously, information of the grain-scale property coupling of elastic strain and domain switching behavior under electric fields has been unobtainable from the bulk of an electro-ceramic material. Here, grain resolved scattering methods have been used to investigate the phase and domain structure of individual grains within bulk polycrystalline electro-ceramic samples under electric field. Example materials are chosen which undergo contrasting strain mechanisms including field-induced phase transformations, and ferroelectric/ferroelastic domain switching. The data obtained show that the grain orientation with respect to the applied electric field vector dictates both the induced phase and degree of domain texturing observed within a given grain. Such knowledge will be of potential benefit to the future engineering of high-strain actuators, but also has implications for all polycrystalline ferroic materials.
        Speaker: John Daniels (UNSW)
      • 10:15
        Gamma irradiation effect on optical and laser damage performance of KDP crystals 15m
        KDP (KH2PO4) is a nonlinear transparent dielectric crystalline material used in various laser systems for harmonic generation. It has been used for inertial confinement fusion in the National Ignition Facility, USA. However, the physical and chemical properties of the KDP crystals may degrade under γ and neutron radiations. Therefore, it is important to understand the effects of radiations on the optical properties especially laser induced damage performance during subsequent laser irradiation. In this work, the effect of Co60 gamma-ray irradiation on KDP crystal with the dose in a range from 1 kGy to 100 kGy is investigated using UV-Vis absorption, fluorescence, DC electrical conductivity, positron annihilation lifetime, and laser induced damage threshold (LIDT). A wide absorption band between 250 and 400 nm appears after γ-irradiation and its intensity increases with the increasing irradiation dose. The dc electrical conductivity of γ-irradiated KDP crystals increases with the increasing irradiation dose when the dose is less than 10 kGy while it remains constantly with the irradiation dose beyond 100 kGy. The increase of electrical conductivity is associated with the increase of proton defect concentration in the crystal and the related mechanism is discussed. The positron annihilation lifetime spectroscopy is also used to reveal the evolution of vacancy-type defects in KDP crystal. The decrease of LIDT and size of vacancy-type clusters with the increasing irradiation dose is also investigated. Short Bio: Wanguo Zheng is the Project Leader of SG-III laser facility in China. He is also the Deputy Director of Research Center for Laser Fusion, China Academy of Engineering Physics. He received his PhD degree in Optical Engineering at Fudan University. In 2011, he was awarded The 14th Qiushi Outstanding Young Scientist of China Association for Science and Technology. His research interests focuses on optical materials and large-aperture optical components, laser engineering and high-power laser technology, and radiation effects of materials. He has published more than 100 scientific papers in international peer-reviewed journals.
        Speaker: Dr Xiaodong Yuan (Research Center of Laser Fusion, China Academy of Engineering Physics)
    • 10:30 → 11:00
      Morning Tea 30m
    • 11:00 → 11:30
      Invited talk: FN1
      • 11:00
        Two-dimensional Coulomb gas at negative temperature 30m
        Lars Onsager is perhaps best known as the recipient of 1968 Nobel Prize in chemistry and by his tour de force solution to the two-dimensional Ising model. However, his remarkable insight predicting the quantisation of vorticity in superfluid helium and the statistical mechanics description of two-dimensional turbulence have received much less attention. In this talk, I will briefly review certain aspects of the problem of two-dimensional turbulence with a particular emphasis on Onsager’s statistical hydrodynamics model. I will then apply this model to turbulent superfluid Bose—Einstein condensates in which the quantised vortices have a long-range effective interaction and can be mapped to a two-dimensional Coulomb gas of positive and negative charged particles. By observing the dynamics of such vortex charges in numerical simulations we have found them to spontaneously arrange to large scale vortex clusters, coined Onsager vortices, that correspond to absolute negative Boltzmann temperatures [1]. I will discuss the microscopic mechanism leading to the emergence of such novel states of matter. Finally, I will outline the recent progress in Australia and elsewhere toward experimentally observing such states [2] with the prospect of realising Onsager’s prediction of super vortices in two-dimensional fluid turbulence. [1] “Emergence of Order from Turbulence in an Isolated Planar Superfluid”, Tapio Simula, Matthew J. Davis, and Kristian Helmerson, Physical Review Letters **113**, 165302 (2014). [2] “Vortex Gyroscope Imaging of Planar Superfluids”, A. T. Powis, S. J. Sammut, and T. P. Simula, Physical Review Letters **113**, 165303 (2014).
        Speaker: Dr Tapio Simula (Monash University)
    • 11:30 → 12:30
      Contributed talk: FN2 - 6
      • 11:30
        Multimode photon-assisted tunnelling in superconducting quantum circuits 15m
        Among the most exciting recent advances in the field of superconducting quantum circuits is the ability to coherently couple microwave photons in low-loss cavities to quantum electronic conductors [1]. These hybrid quantum systems hold great promise for quantum information processing applications, and they enable the exploration of new physical regimes of light-matter interactions. The physics of a tunnel junction illuminated by a purely classical microwave field has been understood since the 1960’s with the classic work of Tien and Gordon [2]. This situation is equivalent to simply having an ac bias voltage across the conductor, and the resulting modification of the current is known as photon-assisted tunneling. Despite the word “photon” in the effect’s name, in this standard formulation there is nothing quantum in the treatment of the applied microwave field. If the cavity is not driven, the cavity-plus-conductor setup realizes another well-studied quantum transport problem: dynamical Coulomb blockade (DCB) [3,4]. Here, the cavity acts as a structured electromagnetic environment for the junction, one that can absorb (and at non-zero temperature, emit) energy from tunnelling electrons. In stark contrast to standard DCB, in Ref. 5 we considered a non-equilibrium environment produced by preparing a microwave cavity in a non-classical (“quantum”) state. The cavity effectively acts as an ac voltage bias across the conductor; by maintaining the cavity in a non-classical state, the junction is exposed to a non-trivial microwave field. We considered stationary, single-mode non-classical microwaves (e.g. squeezed states, Fock states), in the experimentally-relevant situation where a superconducting microwave cavity is coupled to a conductor in the single electron tunneling regime. We found that the conductor functions as a non-trivial probe of the microwave state: the emission and absorption of photons by the conductor is characterized by a non-positive definite quasi-probability distribution which is related to the Glauber-Sudarshan P-function of quantum optics. These negative quasi-probabilities have a direct influence on the conductance of the conductor, and the non-classicality of the microwave field may be inferred directly from features in the current-voltage characteristic. Here we consider the behaviour of a quantum conductor in the presence of stationary, but multimode, structured microwave field environments. We show how the statistics of these microwave fields, including their correlations and entanglement, impact the current and current noise of the coupled conductor. We describe how the statistics of the multimode microwave fields can be inferred through transport measurements alone. 1. K. D. Petersson et al., Nature 490, 380 (2012). 2. P. K. Tien and J. P. Gordon, Phys. Rev. 129, 647 (1963). 3. M. H. Devoret et al., Phys. Rev. Lett. 64, 1824 (1990). 4. S. M. Girvin et al., Phys. Rev. Lett. 64, 3183 (1990). 5. J.-R. Souquet, M. J. Woolley, J. Gabelli, P. Simon, and A. A. Clerk, Nature Communications 5, 5562 (2014).
        Speaker: Dr Matt Woolley (UNSW Canberra)
      • 11:45
        Focusing of electrons and holes in semiconductors: from semi-classical dynamics to spintronics 15m
        The dynamics of charge carriers in spin-orbit coupled systems is a vital area of investigation for the extremely active field of spintronics. Controlling and manipulating the flow of electrons and holes serves as the foundation of an entire class of spintronic devices, most notably the Datta-Das spin transistor \cite{Datta1990}. In this talk, I give an overview of the dynamics of charge carriers in such semiconductor systems, subject to external fields, in the context of magnetic focusing experiments. This experimental technique involves the coherent focusing of charge carriers over a scale of micrometers by a weak magnetic field, from an injector to a collector quantum point contact (QPC) \cite{Vanhouten1989, Rokhinson2004}. I will present a detailed semi-classical theory for the focusing of both electrons and holes for general spin orbit interactions, and show that for the experimentally interesting case of polarization inducing in-plane magnetic fields, a significant change in the magnetic focusing spectrum is possible. \bibitem{Datta1990} S. Datta, and B. Das, {Appl. Phys. Lett. {\bf 56}, 665 (1990). \bibitem{Vanhouten1989} H. Van Houten}, C. W. J. Beenakker, J. G. Williamson, M. E I Broekaart, P. H. M . Van Loosdrecht, B. J. Van Wees, J. E. Mooij, C. T. Foxon, and J. J. Harris, Phys. Rev. B.{\bf 39}, 8556 (1989). \bibitem{Rokhinson2004} L. P. Rokhinson, V Larkina, Y. B. Lyanda-Geller, L. N. Pfeiffer, K. W. West, Phys. Rev. Lett. {\bf 93}, 146601 (2004).
        Speaker: Mr Samuel Bladwell (The University of New South Wales)
    • 12:30 → 12:45
      Closing Remarks
    • 12:45 → 14:00
      Lunch 1h 15m
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