SKM 2021 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 8: Focus Session: Emerging Phenomena in Superconducting Low Dimensional Hybrid Systems II
TT 8.4: Talk
Tuesday, September 28, 2021, 14:15–14:30, H7
Heat-charge separation and nonlocal response in superconductor-InAs nanowire hybrid devices — Artem Denisov1, Gregor Koblmueller2, and •Vadim Khrapai3 — 1Department of Physics, Princeton University, Princeton — 2Walter Schottky Institut, Physik Department, and Center for Nanotechnology and Nanomaterials, TU Muenchen — 3Osipyan Institute of Solid State Physics of the Russian Academy of Sciences
Nonlocal quasiparticle transport in normal-superconductor-normal (NSN) hybrid structures probes sub-gap states in the proximity region. Here we show that a non-local shot noise is a complementary to conductance measurement in superconducting proximity devices. Using NSN InAs nanowire based devices we demonstrate that quasiparticle response is practically charge-neutral. This is qualitatively explained by numerous Andreev reflections of a diffusing quasiparticle, that makes its charge completely uncertain. As a result, the sub-gap response is dominated by the heat transport component with a thermal conductance being on the order of the conductance quantum. By contrast, strong fluctuations and sign reversal are observed in the nonlocal conductance, including occasional Andreev rectification signals. Our results evidence effective heat-charge separaion at the central S-terminal.
We are grateful to our colleagues A. Bubis, S. Piatrusha, N. Titova, A. Nasibulin, J. Becker, J. Treu, D. Ruhstorfer and E. Tikhonov for their contribution to the preprint arXiv:2101.02128 on which this presentation is based.