Quantized conductance doubling and hard gap in a two-dimensional semiconductor-superconductor heterostructure

Quantized conductance doubling and hard gap in a two-dimensional semiconductor-superconductor heterostructure

Kjaergaard, M. (University of Copenhagen)
Nichele, F. (University of Copenhagen)
Suominen, H. J. (University of Copenhagen)
Nowak, M.P. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; AGH University of Science and Technology; Kavli institute of nanoscience Delft)
Wimmer, M (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft)
Akhmerov, A.R. (TU Delft QN/Akhmerov Group; Kavli institute of nanoscience Delft)
Folk, JA (University of British Columbia)
Flensberg, K. (University of Copenhagen)
Shabani, J. (University of California)
Palmstrøm, C. J. (University of California)
Marcus, C. M. (University of Copenhagen)

2016-09-29

Coupling a two-dimensional (2D) semiconductor heterostructure to a superconductor opens new research and technology opportunities, including fundamental problems in mesoscopic superconductivity, scalable superconducting electronics, and new topological states of matter. One route towards topological matter is by coupling a 2D electron gas with strong spin-orbit interaction to an s-wave superconductor. Previous efforts along these lines have been adversely affected by interface disorder and unstable gating. Here we show measurements on a gateable InGaAs/InAs 2DEG with patterned epitaxial Al, yielding devices with atomically pristine interfaces between semiconductor and superconductor. Using surface gates to form a quantum point contact (QPC), we find a hard superconducting gap in the tunnelling regime. When the QPC is in the open regime, we observe a first conductance plateau at 4e 2 /h, consistent with theory. The hard-gap semiconductor-superconductor system demonstrated here is amenable to top-down processing and provides a new avenue towards low-dissipation electronics and topological quantum systems.

http://resolver.tudelft.nl/uuid:5fb612f0-a5a3-4b7c-a399-bf682168c3ea

https://doi.org/10.1038/ncomms12841

2041-1723

Nature Communications, 7, 1-6

Institutional Repository

journal article

© 2016 M. Kjaergaard, F. Nichele, H. J. Suominen, M.P. Nowak, M Wimmer, A.R. Akhmerov, JA Folk, K. Flensberg, J. Shabani, C. J. Palmstrøm, C. M. Marcus