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

Authors

M. Kjaergaard, University of Copenhagen
F. Nichele, University of Copenhagen
H. J. Suominen, University of Copenhagen
M. P. Nowak, Delft University of Technology
M. Wimmer, Delft University of Technology
A. R. Akhmerov, Delft University of Technology
J. A. Folk, University of British Columbia
K. Flensberg, University of Copenhagen
J. Shabani, CUNY City CollegeFollow
C. J. Palmstrom, University of California, Santa Barbara
C. M. Marcus, University of Copenhagen

Document Type

Article

Publication Date

9-29-2016

Abstract

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 4e2/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.

Comments

This article was originally published in Nature Communications, available at DOI: 10.1038/ncomms12841.

This work is licensed under a Creative Commons Attribution 4.0 International License.