Tunable superconductivity in planar Germanium

ORAL

Abstract

III-V materials, like InAs and InSb, are the leading platforms for the realization of gatemons and for the quest of Majorana zero modes. Here we investigate Ge as an alternative platform [1]. In the past years, dramatic progress has been made in inducing superconductivity in planar germanium either by enhancing the proximity effect using a double layer of superconductors [2] or by creating a low-disorder interface between the germanium hole gas and an annealed germanosilicide superconductor [3]. Here, we show that we can reliably induce superconductivity in a germanium hole gas by evaporating aluminum on top of a thin Si0.3Ge0.7 spacer which separates the superconductor from the quantum well. We estimate transparencies close to unity and we reveal a superconducting hard gap which can be tuned by the Si0.3Ge0.7 spacer. Finally, we show the exchange of pairs of Cooper pairs between two superconducting leads, highlighting the potential of Germanium quantum well as protected qubit [4].

[1] G. Scappucci et al., Nature Reviews Materials 6.10 (2021): 926-943.

[2] K. Aggarwal et al., Physical Review Research 3.2 (2021): L022005.

[3] A. Tosato et al., arXiv:2206.00569 (2022).

[4] C. Schrade, et al., PRX Quantum 3.3 (2022): 030303.

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Presenters

  • Marco Valentini

    • Institute of Science and Technology Austria

Authors

  • Marco Valentini

    • Institute of Science and Technology Austria

  • Oliver Sagi

    • Institute of Science and Technology Austria (ISTA), 3400 Klosterneuburg, Austria
    • IST Austria

  • Kushagra Aggarwal

    • University of Oxford

  • Thijs de Gijsel

    • IST Austria

  • Jason Jung

    • Eindhoven University of Technology

  • Marcel Verheijen

    • Eindhoven University of Technology

  • Stefano Calcaterra

    • Politecnico di Milano

  • Andrea Ballabio

    • L-NESS, Physics Department, Politecnico di Milano
    • Politecnico di Milano
    • L-NESS, Physics Department, Politecnico di Milano, 22100 Como, Italy
    • L-NESS, Physics Department, Politecnico di Milano, via Anzani 42, 22100, Como, Italy
    • L-NESS, Politecnico di Milano

  • Daniel Chrastina

    • L-NESS, Physics Department, Politecnico di Milano
    • Politecnico di Milano
    • L-NESS, Physics Department, Politecnico di Milano, 22100 Como, Italy
    • L-NESS, Physics Department, Politecnico di Milano, via Anzani 42, 22100, Como, Italy
    • L-NESS, Politecnico di Milano

  • Erik P. A. M. Bakkers

    • Eindhoven University of Technology

  • Giovanni Isella

    • L-NESS, Physics Department, Politecnico di Milano
    • Politecnico di Milano
    • L-NESS, Physics Department, Politecnico di Milano, 22100 Como, Italy
    • L-NESS, Politecnico di Milano

  • Georgios Katsaros

    • Institute of Science and Technology Austria
    • IST Austria
    • Institute of Science and Technology Austria (ISTA), 3400 Klosterneuburg, Austria
    • Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria