Quantized conductance doubling and hard gap in a two-dimensional semiconductor-superconductor heterostructure.
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.
Center for Quantum Devices and Station Q Copenhagen, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark.
M
M
Kjaergaard
Center for Quantum Devices and Station Q Copenhagen, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark.
F
F
Nichele
Center for Quantum Devices and Station Q Copenhagen, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark.
H J
HJ
Suominen
Kavli Institute of Nanoscience, Delft University of Technology, PO Box 4056, 2600 GA Delft, The Netherlands.|QuTech, Delft University of Technology, PO Box 4056, 2600 GA Delft, The Netherlands.|AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, Mickiewicza 30, 30-059 Kraków, Poland.
M P
MP
Nowak
Kavli Institute of Nanoscience, Delft University of Technology, PO Box 4056, 2600 GA Delft, The Netherlands.|QuTech, Delft University of Technology, PO Box 4056, 2600 GA Delft, The Netherlands.
M
M
Wimmer
Kavli Institute of Nanoscience, Delft University of Technology, PO Box 4056, 2600 GA Delft, The Netherlands.
A R
AR
Akhmerov
Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada V6T1Z1.|Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia, Canada V6T1Z4.
J A
JA
Folk
Center for Quantum Devices and Station Q Copenhagen, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark.
K
K
Flensberg
California NanoSystems Institute, University of California, Santa Barbara, California 93106, USA.
J
J
Shabani
California NanoSystems Institute, University of California, Santa Barbara, California 93106, USA.
C J
CJ
Palmstrøm
Center for Quantum Devices and Station Q Copenhagen, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark.
C M
CM
Marcus
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