CSIRO Lindfield hosting a Seminar by Scientia Professor Alex Hamilton

Quantum Electronic Devices: studying electron flow, making synthetic quantum matter, and operating fast hole spin qubits

Alex is one of Australia’s leading experimental condensed matter physicists, working on topological materials and semiconductor holes in quantum devices. He leads the Quantum Electronic Devices group at UNSW and was the Deputy Director of the ARC Centre for Future Low Energy Electronics Technologies (FLEET) before it concluded in June.

Abstract

I will give an informal overview of 3 topics we are pursuing in the QED group at UNSW:

1. Studying electron flow in 2D materials: the high-school picture of electricity is of a fluid that flows to create an electrical current. In devices made with very clean 2D materials we can study this fluid flow of electricity, which allows a new an ultra-precise method of measuring the Landau liquid quasiparticle lifetime, as well as opening possibilities for engineering new high speed electronic devices. [1]
2. Synthetic quantum matter: The electronic properties of solids are determined by the crystal structure and interactions between electrons, giving rise to a variety of collective phenomena including superconductivity, strange metals and correlated insulators. The mechanisms underpinning many of these collective phenomena remain unknown, driving interest in creating artificial crystals which replicate the system of interest while allowing precise control of key parameters. We have developed new techniques for making electrically defined artificial crystals in 2D systems where we can determine the lattice shape, lattice constant, and band filling. Transport measurements show we can change the mass of the electrons, and turn electrons into holes in this artificial crystal. [2]
3. Fast hole spin qubits in silicon: Spin qubits in quantum dots are attracting significant interest as building blocks for scalable quantum processors. Semiconductor holes allow fast all-electrical spin control via electric-dipole spin resonance (EDSR) using local gate electrodes to both confine and control the hole spins. They also offer rich spin physics, due to spin-3/2 nature of holes and the interplay between quantum confinement, non-uniform strain fields, spin-orbit interaction, and external magnetic fields [3].
   Here I present new results on hole spin qubits in industry standard planar silicon MOS structures fabricated on a 300mm wafer by imec in Belgium. We have demonstrated the first one and two qubit devices in planar silicon, with Rabi frequencies reaching 20 MHz and controllable two-qubit exchange at ~40 MHz and single gate fidelities above 99%. This shows the potential for fabricating high speed hole spin qubits on an industrial scale.

[1]      A.C. Keser, D. Q. Wang et al, Physical Review X, 11, 031030 (2021).

[2]      D.Q. Wang et al, Nano Lett 23, 1705 (2023); D.Q. Wang et al preprint arXiv:2402.12769 (2024).

[3]      Ik Kyeong Jin et al, Nano Letters 23, 1261 (2023); S.D. Liles et al Nature Communications 9, 3255 (2018);
S.D. Liles et al, Nature Communications 15, 7690 (2024).

Biography

Scientia Professor Alexander Hamilton is an ARC Industrial Laureate Fellow at the University of New South Wales, in Sydney. He heads a research group investigating quantum phenomena in nanoscale transistors, with special interests in semiconductor holes which have applications to future electronics and information processing technologies, and in new materials for low energy electronics.

He has co-founded two ARC Centres of Excellence (the ARC Centre of Excellence for Future Low Energy Electronics and the ARC Centre of Excellence for Quantum Computer Technology), served 6 years as a member of the ARC College of Experts, was awarded 3 ARC and one EPSRC fellowships, and is a Fellow of the American Institute of Physics. He has established research collaborations with industry (NTT in Japan, imec in Belgium, Diraq in Australia), as well as major international institutions, including the University of Cambridge (UK), ETH Zurich and the university of Basel (Switzerland), the Technical University of Delft (Netherlands), the Niels Bohr Institute (Denmark), the MacDiarmid Institute (New Zealand), and the University of Salamanca (Spain), and has raised funding to enable students and early career researchers to travel and work for extended periods with many of these collaborators.

If you are interested in attending please contact:

Dr Golrokh Akhgar: golrokh.akhgar@csiro.au

Research Scientist  |  Unconventional Thin Films  |  Devices and Engineered Systems / Quantum Sensors
Manufacturing |  CSIRO