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

TY - JOUR

T1 - Quantized conductance doubling and hard gap in a two-dimensional semiconductor-superconductor heterostructure

AU - Kjærgaard, Morten

AU - Nichele, F

AU - Suominen, Henri Juhani

AU - Nowak, M P

AU - Wimmer, M

AU - Akhmerov, A R

AU - Folk, J A

AU - Flensberg, Karsten

AU - Shabani, J

AU - Palmstrøm, C J

AU - Marcus, Charles M.

N1 - [Qdev]

PY - 2016/9/29

Y1 - 2016/9/29

N2 - 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.

AB - 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.

U2 - 10.1038/ncomms12841

DO - 10.1038/ncomms12841

M3 - Journal article

C2 - 27682268

SN - 2041-1723

VL - 7

JO - Nature Communications

JF - Nature Communications

M1 - 12841

ER -