Cole, Jared

Date:  Friday, April 13, 2018
Time:  14:00
Place:  ETH Zurich, Hönggerberg, HPF G 6
Host:  Clemens Müller/Gianni Blatter

The materials science of Josephson junctions: modelling transport through them and probing the defects within

Jared Cole
RMIT University Melbourne, Australia

Superconducting circuits are one of the best understood and most promising devices for realising controllable qubits in solid-state systems. Unfortunately their performance is directly limited by the quality of the Josephson junctions within the circuit. These in turn are comprised of amorphous metal-oxide layers. We are developing computational models of the fabrication process to help understand how these oxides are formed and what controls their electrical response. These ultra-thin layers and the encasing surface oxide of the circuit also contain defects comprised of uncontrolled two-level systems (TLS). Ironically, the performance of these very modern circuits are therefore limited by a much older and well-known problem from solid-state physics; what is the origin of the low temperature behaviour of amorphous glasses? Developing better computational models amorphous metal-oxides may therefore result in not just better qubits, but new understanding of fundamental solid-state physics.