Hard superconducting gap in germanium

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 hy...

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Detalles Bibliográficos
Autores: Tosato, Alberto, Levajac, Vukan, Wang, Ji-Yin, Boor, Casper J., Borsoi, Francesco|||0000-0001-9398-7614, Botifoll, Marc|||0000-0002-4876-6393, Borja, Carla, Martí-Sánchez, Sara|||0000-0003-4283-1489, Arbiol i Cobos, Jordi|||0000-0002-0695-1726, Sammak, Amir, Veldhorst, Menno|||0000-0001-9730-3523, Scappucci, Giordano|||0000-0003-2512-0079
Tipo de recurso: artículo
Fecha de publicación:2023
País:España
Institución:Universitat Autònoma de Barcelona
Repositorio:Dipòsit Digital de Documents de la UAB
Idioma:inglés
OAI Identifier:oai:ddd.uab.cat:287079
Acceso en línea:https://ddd.uab.cat/record/287079
https://dx.doi.org/urn:doi:10.1038/s43246-023-00351-w
Access Level:acceso abierto
Palabra clave:Cointegration
Germaniums (Ge)
High mobility
High-fidelity
Josephson-junction
Quantum information technologies
Spin systems
Spin-s systems
Superconducting gaps
Topological systems
Descripción
Sumario: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.