Electrostatic control of the proximity effect in the bulk of semiconductor-superconductor hybrids

Electrostatic control of the proximity effect in the bulk of semiconductor-superconductor hybrids

van Loo, N. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Eindhoven University of Technology; Kavli institute of nanoscience Delft)
Mazur, G.P. (TU Delft QRD/Wimmer Group; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft)
Dvir, T. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft)
Wang, Guanzhong (TU Delft QRD/Wimmer Group; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft)
Dekker, R.C. (TU Delft QN/Steele Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft)
Lemang, M.F. (TU Delft QN/Afdelingsbureau; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft)
Sfiligoj, C. (TU Delft BUS/Quantum Delft; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft)
Bordin, A. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft)
van Driel, D. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft)
Kouwenhoven, Leo P. (TU Delft QN/Kouwenhoven Lab; Kavli institute of nanoscience Delft)

2023

The proximity effect in semiconductor-superconductor nanowires is expected to generate an induced gap in the semiconductor. The magnitude of this induced gap, together with the semiconductor properties like spin-orbit coupling and g-factor, depends on the coupling between the materials. It is predicted that this coupling can be adjusted through the use of electric fields. We study this phenomenon in InSb/Al/Pt hybrids using nonlocal spectroscopy. We show that these hybrids can be tuned such that the semiconductor and superconductor are strongly coupled. In this case, the induced gap is similar to the superconducting gap in the Al/Pt shell and closes only at high magnetic fields. In contrast, the coupling can be suppressed which leads to a strong reduction of the induced gap and critical magnetic field. At the crossover between the strong-coupling and weak-coupling regimes, we observe the closing and reopening of the induced gap in the bulk of a nanowire. Contrary to expectations, it is not accompanied by the formation of zero-bias peaks in the local conductance spectra. As a result, this cannot be attributed conclusively to the anticipated topological phase transition and we discuss possible alternative explanations.

http://resolver.tudelft.nl/uuid:9539c468-9e56-4683-a1e2-6fa528298d70

https://doi.org/10.1038/s41467-023-39044-w

Nature Communications, 14 (1)

Institutional Repository

journal article

© 2023 N. van Loo, G.P. Mazur, T. Dvir, Guanzhong Wang, R.C. Dekker, M.F. Lemang, C. Sfiligoj, A. Bordin, D. van Driel, Leo P. Kouwenhoven, More Authors