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

Morten Kjærgaard, F Nichele, Henri Juhani Suominen, M P Nowak, M Wimmer, A R Akhmerov, J A Folk, Karsten Flensberg, J Shabani, C J Palmstrøm, Charles M. Marcus

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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 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.

Original languageEnglish
Article number12841
JournalNature Communications
Volume7
Number of pages6
ISSN2041-1723
DOIs
Publication statusPublished - 30 Sep 2016

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