Welcome to the web page of the Quantum Electronic Devices group in UNSW's School of Physics
The Quantum Electronic Devices group (@QEDUNSW) is part of the Condensed Matter department in UNSW's School of Physics in the heart of Sydney. We are a key laboratory in 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.
12 Aug 2021
A new approach to making ultra-low noise quantum devices from a single crystal: Yonatan's new paper in Applied Physics Letters, selected as an Editor’s pick, reports a new way to make transistors in which the metal gate electrode is grown as part of the single crystal heterostructure. This eliminates unwanted charge noise and scattering from surface states, and allows ultra-shallow, high mobility 2D electron systems and stable quantum devices:
Y. Ashlea Alava, D. Q. Wang, C. Chen, D. A. Ritchie, O. Klochan, and A. R. Hamilton, High electron mobility and low noise quantum point contacts in an ultra-shallow all-epitaxial metal gate GaAs/AlxGa1−xAs heterostructure, Appl. Phys. Lett. 119, 063105 (2021). https://doi.org/10.1063/5.0053816
- 6 Aug 2021
- Congratulations to Aydin and Daisy: their paper in Physical Review X, reporting that electrons in a transistor can behave like a super-viscous fluid, has been selected for a feature article in the American Physical Society’s Physics Magazine: https://physics.aps.org/articles/v14/115
- 1 May 2021
- We are hiring! We have an opening for a postdoctoral research fellow to work on experimental measurement of hole spin qubits (Hole_Spin_Qubits_2021_Advert.pdf). Spin-3/2 holes are cool because you can manipulate their magnetic spin just with an electric field, and they have lots of interesting properties that electrons don't. Some details on the position are here: https://external-careers.jobs.unsw.edu.au/cw/en/job/501827/postdoctoral-fellow. One of our recent works is here https://arxiv.org/abs/2012.04985, and others are linked below:
- 2 Apr 2021
- Two new papers on the theory of hole spin qubits:
Zhanning and colleagues' new results overturn the conventional wisdom that fast operation implies reduced lifetimes in spin qubits, and suggest group IV hole spin qubits are an ideal platforms for ultra-fast, highly coherent scalable quantum computing.
Z. Wang, E. Marcellina, A.R. Hamilton, J. H. Cullen, S. Rogge, J. Salfi and D. Culcer,
Optimal operation points for ultrafast, highly coherent Ge hole spin-orbit qubits, npj Quantum Inf. 7, 54 (2021). https://doi.org/10.1038/s41534-021-00386-2
This is complemented by a second paper in PRB reports which investigates the properties of germanium hole spin qubits:
LA Terrazos, E Marcellina, Zhanning Wang, SN Coppersmith, Mark Friesen, AR Hamilton, Xuedong Hu, Belita Koiller, AL Saraiva, Dimitrie Culcer, Rodrigo B Capaz,
Theory of hole-spin qubits in strained germanium quantum dots, Physical Review B 103, 125201 (2021). https://arxiv.org/abs/1803.10320 and https://doi.org/10.1103/PhysRevB.103.125201
- 17 Mar 2021
- Our new study of hydrodynamic flow of an electron liquid in a perfect pipe is on the archive.
This is really neat - fluid flow has major practical consequences, from lab on a chip devices to rocket design. At low temperatures the motion of electrons in clean solid, which we usually think of as individual particles bouncing around off impurities and thermal vibrations, is transformed into the collective motion of a viscous fluid. The fluid viscosity is a universal and intrinsic property of the electron system. However this universal nature is hard to detect experimentally, as hydrodynamics is mainly detected through the interaction of the fluid with the sample boundaries (think of a rough pipe vs a smooth pipe), and this is an unknown quantity that varies between experiments. In their preprint Aydin and Daisy eliminated the boundary problem by creating electronic devices with perfectly smooth walls, and then reintroduced viscous flow by engineering obstacles into the boundaries. This made it possible to clearly observe a transition to hydrodynamic electron motion, driven by decreasing temperature (which is expected) and also by increasing magnetic field (which is not). The precision of the new experiments allowed the electron quasiparticle lifetime to be measured over a wide temperature range, revealing an unexpected deviation from existing theoretical models.
Aydın Cem Keser, Daisy Q. Wang, Oleh Klochan, Derek Y. H. Ho, Olga A. Tkachenko, Vitaly A. Tkachenko, Dimitrie Culcer, Shaffique Adam, Ian Farrer, David A. Ritchie, Oleg P. Sushkov, Alexander R. Hamilton, Geometric control of universal hydrodynamic flow in a two dimensional electron fluid, https://arxiv.org/abs/2103.09463.
- 4 Jan 2021
- Karina's paper reporting a new way to detect the spin-gap, a pre-requisite for topological Majorana Zero Modes, has just appeared in Nature Communications! Congratulations on a beautiful experiment and theory collaboration.
K. L. Hudson, A. Srinivasan, O. Goulko, J. Adam, Q. Wang, L. A. Yeoh, O. Klochan, I. Farrer, D. A. Ritchie, A. Ludwig, A. D. Wieck, J. von Delft & A. R. Hamilton, New signatures of the spin gap in quantum point contacts,
Nature Communications 12, 5 (2021). https://doi.org/10.1038/s41467-020-19895-3
- 18 Dec 2020
- Congratulations to three undergraduates who have won six week summer research scholarships: Cory Aitchison and Nick Zaunders won Sydney Quantum Academy Undergraduate Research Scholarships, and Krittika Kumar won a FLEET scholarship. See what they got up to here: https://twitter.com/FLEETCentre/status/1366878577740800003
- 4 Nov 2020
- Our new results showing how to dramatically improve the reproducibility of quantum devices (needed if we are going to scale them up to complex circuits) has just been published:
A. Srinivasan, I. Farrer, D. A. Ritchie, and A. R. Hamilton, Improving reproducibility of quantum devices with completely undoped architectures, Appl. Phys. Lett. 117, 183101 (2020). https://arxiv.org/abs/2011.04119v1 and https://doi.org/10.1063/5.0024923.
- 27 Oct 2020
- Summer Vacation Scholarships are available in the QED group for high achieving undergraduate students. Details are here SummerVacationScholarships2020.
- August 2020
- Congratulations to Karina Hudson, who has been awarded a highly-competitive 3 year Sydney Quantum Academy Fellowship (equivalent to a DECRA).
- 23 Jul 2020
- Congratulations to Daisy Wang on her paper in Applied Physics Letters reporting a new approach to making lateral surface superlattices for artificial crystals in conventional electronic transistors: DQ Wang, D Reuter, AD Wieck, AR Hamilton, and O Klochan: "Two-dimensional lateral surface superlattices in GaAs heterostructures with independent control of carrier density and modulation potential", Applied Physics Letters 117 (3), 032102 (2020). https://doi.org/10.1063/5.0009462
- 15 Jul 2020
- Applications now open for the 2020 Sydney Quantum Academy Postdoctoral Fellowships. Closing date: Tuesday 11 August 2020. The QED team offers projects in topological systems and quantum computing.To apply, click here. Contact email@example.com and cc: firstname.lastname@example.org for further information.
- 13 May 2020
- Sydney Quantum Academy Postgraduate PhD Scholarships The QED team currently offers PhD projects in topological systems and quantum computing. For more information and to apply, click here. Contact email@example.com and CC: firstname.lastname@example.org for further information.
- 29 Feb 2020
- Another Rapid Communication in Physical Review B: With David Neilson and our collaborators in Europe we have a new paper on excitonic superfluidity in semiconductor devices: "Experimental conditions for observation of electron-hole superfluidity in GaAs heterostructures", Samira Saberi-Pouya, Sara Conti, Andrea Perali, Andrew F. Croxall, Alexander R. Hamilton, Francois M. Peeters, David Neilson. A preprint is here: https://arxiv.org/abs/1910.06631
- 24 Feb 2020
- Congratulations to Dr. Liles upon the award of his Ph.D. thesis “Single hole spins in silicon quantum dots”.
- 21 Feb 2020
- First paper of the year: Congratulations to Elizabeth Marcellina, whose paper reporting a new signature of topological physics in classical physics properties has just been been accepted for publication as a Rapid Communication in Physical Review B: "Signatures of quantum mechanical Zeeman effect in classical transport due to topological properties of two-dimensional spin-3/2 holes", E. Marcellina, Pankaj Bhalla, A. R. Hamilton, Dimitrie Culcer. The preprint is here: https://arxiv.org/abs/1906.11439
- 11 Feb 2020
- Scott Liles is at ICONN 2020 presenting a talk on Strong electric control of a single hole g-factor
- 22 Jan 2020
- We're excited to be installing our new dilution fridge, and have already made some cutting edge breakthroughs in an effort to deepen the understanding of holes. Link.
- 20 Dec 2019
- Congratulations to Dr. Karina Hudson, who has just been awarded a Dean’s Award for her Outstanding PhD Thesis.
- 11 Dec 2019
- Well done again to Matthew Rendell, who won a best poster award at the FLEET annual workshop.
- 4 Dec 2019
- New funding for QED research. Alex Hamilton, with collaborators Daniel Loss in Basel, Giordano Scappucci in TU Delft, and David Ritchie in Cambridge, have won an ARC Discovery Grant to investigate hole spins for quantum information applications.