An InAsSb surface quantum well with in-situ deposited Nb as a platform for semiconductor-superconductor hybrid devices

Sjoerd Telkamp; Zijin Lei; Tommaso Antonelli; Christian Reichl; Ilya Besedin; Georg Jakobs; Stefan Fält; Christian Marty; Rüdiger Schott; Werner Wegscheider

arXiv · 2510.00711

An InAsSb surface quantum well with in-situ deposited Nb as a platform for semiconductor-superconductor hybrid devices

Sjoerd Telkamp·Zijin Lei·Tommaso Antonelli·Christian Reichl·Ilya Besedin·Georg Jakobs·Stefan Fält·Christian Marty·Rüdiger Schott·Werner Wegscheider

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Abstract

We present a novel semiconductor-superconductor hybrid material based on a molecular beam epitaxially grown InAsSb surface quantum well with an in-situ deposited Nb top layer. Relative to conventional Al-InAs based systems, the InAsSb surface quantum well offers a lower effective mass and stronger spin-orbit interaction, while the Nb layer has a higher critical temperature and a larger critical magnetic field. The in-situ deposition of the Nb results in a high-quality interface that enables strong coupling to the InAsSb quantum well. Transport measurements on Josephson junctions reveal an induced superconducting gap of 1.3 meV. Furthermore, a planar asymmetric SQUID is realized, exhibiting gate-tunable superimposed oscillations originating from both the individual Josephson junction and the full SQUID loop. The large induced superconducting gap combined with strong spin-orbit interaction position this material as an attractive platform for experiments exploring gate-tunable superconductivity and topological superconducting devices.

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Sjoerd Telkamp, Zijin Lei, Tommaso Antonelli, Christian Reichl, Ilya Besedin, Georg Jakobs, Stefan Fält, Christian Marty, Rüdiger Schott, Werner Wegscheider. 2025-10-01. An InAsSb surface quantum well with in-situ deposited Nb as a platform for semiconductor-superconductor hybrid devices. https://arxiv.org/abs/2510.00711

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