We experimentally investigate Andreev transport through the interface between an indium superconductor and the edge of the InAs/GaSb bilayer. To cover all possible regimes of InAs/GaSb spectrum, we study samples with 10 nm, 12 nm, and 14 nm thick InAs quantum wells. For the trivial case of a direct band insulator in 10~nm samples, differential resistance demonstrates standard Andreev reflection. For InAs/GaSb structures with band inversion (12~nm and 14 nm samples), we observe distinct low-energy structures, which we regard as direct evidence for the proximity-induced superconductivity within the current-carrying edge state. For 14~nm InAs well samples, we additionally observe mesoscopic-like resistance fluctuations, which are subjected to threshold suppression in low magnetic fields.
@article{arxiv.1710.11375,
title = {Proximity-induced superconductivity within the InAs/GaSb edge conducting state},
author = {A. Kononov and V. A. Kostarev and B. R. Semyagin and V. V. Preobrazhenskii and M. A. Putyato and E. A. Emelyanov and E. V. Deviatov},
journal= {arXiv preprint arXiv:1710.11375},
year = {2017}
}