Welcome to the web page of the Quantum Electronic Devices group in UNSW's School of Physics
QED group May 2016 |
The QED group
The Quantum Electronic Devices group is part of the Condensed Matter department in UNSW's School of Physics
in the heart of Sydney. We are also associated with the Australian Research Council Centre of Excellence for Future Low Energy Electronics Technologies.
Our research examines the fundamental properties of low dimensional systems realised in advanced semiconductor devices, and the development of new semiconductor and superconducting devices.
- 16 November 2017
- Congratulations to Dr. Elizabeth Marcellina !
- 30 October 2017
- The 2017 Gordon Godfrey Workshop on Spins and Strong Correlations will be held at UNSW from Monday 30th October – Friday 3rd November, with an impressive line-up of leading national and international speakers.
The workshop is FREE, and we are particularly encouraging Honours students, Masters/PhD, postdocs and ECRs to attend. There will also be an evening poster session for which we are encouraging submissions. We look forward to seeing you there.
- 27 September 2017
- Some of UNSW's first year science students have been having fun measuring the Quantum Hall Effect in the QED group research labs under the watchful supervision of Karina Hudson, a PhD student in the QED group. The students used a helium-3 refrigerator to cool ultra-high quality gallium arsenide semiconductor chips to -273.4°C (0.25 degrees above absolute zero), and a superconducting magnet to study the Hall effect. The chips contain a thin (two-dimensional) sheet of highly mobile electrons, and at these low temperatures the students confirmed that the Hall resistance develops flat plateaus, where the Hall resistance depends only on the electron charge and Planck's constant, while the resistivity drops to zero. The unexpected discovery of the quantum Hall effect resulted in the 1985 Nobel Prize in Physics (and the fractional quantum Hall effect resulted in the 1998 Nobel Prize in Physics).
- 22 August 2017
- Welcome to new group member Jonathan Ashlea-Alava, who joins us from Spain to start his PhD.
- 14 August 2017
- Congratulations to Dima and Ashwin, whose combined theory and experimental paper resolving a 10-year old mystery has just been accepted into Physical Review Letters.
More than a decade ago QED researchers showed that the Zeeman splitting of holes in 1D wires was much larger if the magnetic field is applied along the wire than perpendicular to it, and this result was later confirmed by several other experimental groups. The anisotropic Zeeman splitting is a manifestation of the spin-orbit interaction, however, the mechanism of the effect has remained unclear in spite of a decade of intensive experimental and theoretical work. In the new work Dima Miserev and Oleg Sushkov show that this anisotropy is due to a new contribution to the Zeeman spin splitting that has previously been overlooked. A preprint is available here:
Mechanisms for strong anisotropy of in-plane g-factors in hole based quantum point contacts, D. S. Miserev, A. Srinivasan, I. Farrer, D. A. Ritchie, A. R. Hamilton, and O. P. Sushkov, https://arxiv.org/abs/1612.00572.
- 20 July 2017
- Welcome to new QED group member Frederico Martins, who joins us from the Niels Bohr Institue in Copenhagen.
- 30 June 2017
- A generously funded Scientia Scholarship is available to for a PhD project to study hole quantum dots.
The scholarship is fully funded for 4 years (including all university tuition fees, AUS$40k (US$30k) annually for living expenses, and an additional research/travel budget), and is open to applicants from any nationality.
The research project will investigate hole spins in quantum dots. In the past decade intense research has been devoted in trapping electrons trapped in semiconductor quantum dots, initially to study the fundamental properties of artificial atoms, and subsequently to use the spin of the electrons as the basis for quantum information technologies.
To date almost all research has focussed on the properties of electrons in semiconductor quantum dots. However very recent theoretical work suggests that that using positively charged semiconductor holes, rather than negatively charged electrons, may bring significant advantages – as well revealing much unexplored new physics. This is because of the much stronger spin-orbit interaction that exists in holes than electrons, allowing the hole spins to be manipulated simply by applying an electric field. The PhD candidate will study holes trapped in semiconductor quantum dots, to perform all electrical control of hole spins, and to test if holes can make good quantum bits. Experiments will be conducted at ultra-low temperatures, using ultra-low noise electrical measurement and control techniques.
The project is a collaborative effort between Scientia Professor Alex Hamilton in the Department of Physics and Scientia Professor Andrew Dzurak in the department of Electrical Engineering & Telecommunications.
- 8 June 2017
- Four fridges cold! We have all four dilution fridges cold, running lots of cool experiments.
- 5 May 2017
- Jo-Tzu and Elizabeth's paper on the theory of spin-bloackade of holes in quantum dots been accepted for publication in PRB: "Spin blockade in hole quantum dots: Tuning exchange electrically and probing Zeeman interactions", J.T. Hung, E. Marcellina, B. Wang, A. R. Hamilton, and D. Culcer, Phys. Rev. B 95, 195316 (2017), https://doi.org/10.1103/PhysRevB.95.195316.
- 10 Apr 2017
- Scott and Daisy have gone to Denmark to conduct experiments at the Centre for Quantum Devices in the Niels Bohr Institute at the University of Copenhagen. Have a great trip!
- 5 Apr 2017
- Well done to Ashwin, Dima and Karina; their paper showing that we can detect the signatures of Rashba and Dresselhaus spin-orbit interactions in hole quantum point contacts, and even control their interplay by changing the substrate orientation, has just been published in Physical Review Letters: "Detection and Control of Spin-Orbit Interactions in a GaAs Hole Quantum Point Contact", A. Srinivasan, D. S. Miserev, K. L. Hudson, O. Klochan, K. Muraki, Y. Hirayama, D. Reuter, A. D. Wieck, O. P. Sushkov, and A. R. Hamilton, Phys. Rev. Lett. 118, 146801 (2017). https://doi.org/10.1103/PhysRevLett.118.146801 with a preprint here: https://arxiv.org/abs/1703.04233.
- 1 Feb 2017
- The new fridge, which we are thinking will either be called Dreadnought or Leviathan, cools below 7mK.
- 17 Jan 2017
- Congratulations to Elizabeth on her first paper! Her work on the theory of 2D hole systems in heterojunction devices in different material systems has been accepted for PRB and chosen as an Editor's choice: "Spin-orbit interactions in inversion-asymmetric two-dimensional hole systems: A variational analysis", E. Marcellina, A. R. Hamilton, R. Winkler, and Dimitrie Culcer, to appear in Phys Rev B. Preprint is here https://arxiv.org/abs/1604.08759.
- 23 Jan 2017
- Installation of our new fridge has started - see BlueForsxLDFridgeInstallationTimelapse for details.
- 24 Nov 2016
- Well done to Daisy, whose paper reporting the first measurements of anisotropic spin blockade in a spin-3/2 heavy hole system has just been accepted for publication in Nano Letters: D.Q. Wang, O. Klochan, J-T Hung, D. Culcer, I. Farrer, D.A. Ritchie, and .R. Hamilton, Anisotropic Pauli Spin Blockade of Holes in a GaAs Double Quantum Dot, Nano Lett., accepted: November 24, (2016). http://dx.doi.org/10.1021/acs.nanolett.6b03752
- 8 Sept 2016
- Congratulations to Oleh Klochan, Oleg Sushkov, Dimi Culcer and Alex Hamilton in the School of Physics, as well as Jan Seidel and Nagarajan Valanoor in the School of Materials Science and Engineering, on the successful ARC Centre of Excellence in Future Low Energy Electronics Technologies (FLEET). The Centre will receive $33M in ARC funding over the next 7 years. It is headquartered at Monash University, with a major presence at UNSW, and will develop the scientific foundations for fundamentally new types of electronic conduction based on topological properties of matter, with potential for future low energy electronics technologies.
- 18 July 2016
- Well done to Ashwin, Karina and Dima - their paper reporting a direct measurement of the magnitude and sign of the g-factor of holes in a quantum point contact has just appeared as a Rapid Communication in Physical Review B: A. Srinivasan, K. L. Hudson, D. Miserev, L. A. Yeoh, O. Klochan, K. Muraki, Y. Hirayama, O. P. Sushkov, and A. R. Hamilton, Electrical control of the sign of the g factor in a GaAs hole quantum point contact, Phys. Rev. B 94, 041406(R) (2016). http://dx.doi.org/10.1103/PhysRevB.94.041406
- 8 July 2016
- Congratulations to Daisy Wang and Oleh Klochan - their paper on a novel double layer gate architecture for making hole quantum dots has just been published: D Q Wang, A R Hamilton, I Farrer, D A Ritchie and O Klochan, Double-layer-gate architecture for few-hole GaAs quantum dots, Nanotechnology 27, 334001 (2016). http://dx.doi.org/10.1088/0957-4484/27/33/334001
- 17 May 2016
- Congratulations to Golrokh Akhgar (LaTrobe), Oleh Klochan (UNSW) and Chris Pakes' diamond team at LaTrobe University: their paper reporting that it is possible to tune the strength of the spin-orbit interaction of 2D holes in surface conducting diamond transistors, has just been accepted by Nano Letters: Strong and Tunable Spin–Orbit Coupling in a Two-Dimensional Hole Gas in Ionic-Liquid Gated Diamond Devices, G. Akhgar, O. Klochan, L.H. Willems van Beveren, M.T. Edmonds, F. Maier, B.J. Spencer, J.C. McCallum, L. Ley, A.R. Hamilton, and C.I. Pakes, Nano Letters (in press, 2016). See http://dx.doi.org/10.1021/acs.nanolett.6b01155.
- 25 April 2016
- Congratulations to Tommy Li and LaReine Yeoh - their paper reporting the observation of non-adiabatic spin dynamics (equivalent to a non-abelian Berry phase) in a 2D hole system has just been accepted for publication: Manifestation of a non-Abelian Berry phase in a p-type semiconductor system, T. Li, L.A. Yeoh, A. Srinivasan, O. Klochan, D. A. Ritchie, M.Y. Simmons, O.P. Sushkov, and A.R. Hamilton, Physical Review B 93, 205424 (2016). See http://dx.doi.org/10.1103/PhysRevB.93.205424
- 11 Mar 2016
- Elizabeth Marcellina is off to Baltimore to present her work at the 2016 March Meeting of the American Physical Society.
- 29 Feb 2016
- Welcome to new Honours student Jarrod Adam.
- 31 Jan 2016
- Congratulations to Dr. Daisy Wang !
- 28 Jan 2016
- Congratulations to Matt Rendell, whose paper on magnetic focussing of holes has been selected by the Editorial Board as one of the Semiconductor Science and Technology Highlights of 2015.
- 18 Jan 2016
- Welcome to two new group members: Honours student Yonatan, and undergraduate vacation scholar Isaac.
- 7 Jan 2016
- Congratulations to Dr. Roy Li !