Schmitt, T W; Connolly, M R; Schleevoigt, M; Liu, C; Kennedy, O; Chavez-Garcia, J M; Jalil, A R; Bennemann, B; Trellenkamp, S; Lentz, F; Neumann, E; Lindstrom, T; de Graaf, S E; Berenschot, E; Tas, N; Mussler, G; Petersson, K D; Grutzmacher, D; Schuffelgen, P (2022) Integration of topological insulator Josephson junctions in superconducting qubit circuits. Nano Letters, 22 (7). pp. 2595-2602.

Full text not available from this repository.

Abstract

The integration of semiconductor Josephson junctions (JJs) in superconducting quantum circuits provides a scalable platform for voltage-controlled hybrid qubits and offers a powerful way to probe quasiparticle excitations in quantum materials. Recent advances with using circuit quantum electrodynamics (cQED) to investigate III-V semiconductors motivates the exploration of novel strong spin-orbit materials. Here, we report on the realisation of superconducting transmon qubits integrated with V-VI topological insulator (TI) JJs. Our fabrication process combines precise and clean in situ definition of JJs on the nm-scale with ex situ patterning of the mm-sized transmon circuitry. Using the cavity-qubit interaction we show that the Josephson energy scales with JJ dimensions. We demonstrate coherent control of the transmon and extract coherence times of ~30 ns. Microwave losses in the substrate imply microsecond relaxation times, indicating additional loss mechanisms in the JJ that can be investigated in future gate-tuneable devices. Our results thus pave the way for integration of topological materials into both novel voltage-controlled Josephson and topological qubits.

Item Type:	Article
Subjects:	Quantum Phenomena > Nanophysics
Divisions:	Quantum Technologies
Identification number/DOI:	10.1021/acs.nanolett.1c04055
Last Modified:	27 Apr 2022 12:53
URI:	https://eprintspublications.npl.co.uk/id/eprint/9405