Hard superconducting gap in germanium
Tosato, Alberto (Delft University of Technology)
Levajac, Vukan (Delft University of Technology)
Wang, Ji-Yin (Delft University of Technology)
Boor, Casper J. (Delft University of Technology)
Borsoi, Francesco (Delft University of Technology)
Botifoll, Marc (Institut Català de Nanociència i Nanotecnologia)
Borja, Carla (Institut Català de Nanociència i Nanotecnologia)
Martí-Sánchez, Sara (Institut Català de Nanociència i Nanotecnologia)
Arbiol i Cobos, Jordi (Institut Català de Nanociència i Nanotecnologia)
Sammak, Amir (QuTech and Netherlands Organisation for Applied Scientific Research)
Veldhorst, Menno (Delft University of Technology)
Scappucci, Giordano (Delft University of Technology)

Date:	2023
Abstract:	The co-integration of spin, superconducting, and topological systems is emerging as an exciting pathway for scalable and high-fidelity quantum information technology. High-mobility planar germanium is a front-runner semiconductor for building quantum processors with spin-qubits, but progress with hybrid superconductor-semiconductor devices is hindered by the difficulty in obtaining a superconducting hard gap, that is, a gap free of subgap states. Here, we address this challenge by developing a low-disorder, oxide-free interface between high-mobility planar germanium and a germanosilicide parent superconductor. This superconducting contact is formed by the thermally-activated solid phase reaction between a metal, platinum, and the Ge/SiGe semiconductor heterostructure. Electrical characterization reveals near-unity transparency in Josephson junctions and, importantly, a hard induced superconducting gap in quantum point contacts. Furthermore, we demonstrate phase control of a Josephson junction and study transport in a gated two-dimensional superconductor-semiconductor array towards scalable architectures. These results expand the quantum technology toolbox in germanium and provide new avenues for exploring monolithic superconductor-semiconductor quantum circuits towards scalable quantum information processing.
Grants:	European Commission 850641 Agència de Gestió d'Ajuts Universitaris i de Recerca 2021/SGR-327 Agencia Estatal de Investigación CEX2021-001214-S
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Subject:	Cointegration ; Germaniums (Ge) ; High mobility ; High-fidelity ; Josephson-junction ; Quantum information technologies ; Spin systems ; Spin-s systems ; Superconducting gaps ; Topological systems
Published in:	Communications Materials, Vol. 4 (April 2023) , art. 23, ISSN 2662-4443

DOI: 10.1038/s43246-023-00351-w

9 p, 2.5 MB

The record appears in these collections:
Research literature > UAB research groups literature > Research Centres and Groups (research output) > Experimental sciences > Catalan Institute of Nanoscience and Nanotechnology (ICN2)
Articles > Research articles
Articles > Published articles