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Andreev reflection spectroscopy in strongly paired superconductors

Lewandowski, Cyprian and Lantagne-Hurtubise, Étienne and Thomson, Alex and Nadj-Perge, Stevan and Alicea, Jason (2022) Andreev reflection spectroscopy in strongly paired superconductors. . (Unpublished)

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Motivated by recent experiments on low-carrier-density superconductors, including twisted multilayer graphene, we study signatures of the BCS to BEC evolution in Andreev reflection spectroscopy. We establish that in a standard quantum point contact geometry, Andreev reflection in a BEC superconductor is unable to mediate a zero-bias conductance beyond e²/h per lead channel. This bound is shown to result from a duality that links the sub-gap conductance of BCS and BEC superconductors. We then demonstrate that sharp signatures of BEC superconductivity, including perfect Andreev reflection, can be recovered by tunneling through a suitably designed potential well. We propose various tunneling spectroscopy setups to experimentally probe this recovery.

Item Type:Report or Paper (Discussion Paper)
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URLURL TypeDescription Paper
Lewandowski, Cyprian0000-0002-6944-9805
Lantagne-Hurtubise, Étienne0000-0003-0417-6452
Thomson, Alex0000-0002-9938-5048
Nadj-Perge, Stevan0000-0002-2916-360X
Alicea, Jason0000-0001-9979-3423
Additional Information:Attribution 4.0 International (CC BY 4.0). We thank Mohit Randeria, Hyunjin Kim, Micha l Papaj, and Kevin Nuckolls for insightful discussions. This work was supported by the Gordon and Betty Moore Foundation’s EPiQS Initiative, Grant GBMF8682 (C.L. and É.L.-H.); the Army Research Office under Grant Award W911NF-17-1-0323; the Caltech Institute for Quantum Information and Matter, an NSF Physics Frontiers Center with support of the Gordon and Betty Moore Foundation through Grant GBMF1250; and the Walter Burke Institute for Theoretical Physics at Caltech.
Group:Institute for Quantum Information and Matter, Walter Burke Institute for Theoretical Physics
Funding AgencyGrant Number
Gordon and Betty Moore FoundationGBMF8682
Army Research Office (ARO)W911NF-17-1-0323
Institute for Quantum Information and Matter (IQIM)UNSPECIFIED
Gordon and Betty Moore FoundationGBMF1250
Walter Burke Institute for Theoretical Physics, CaltechUNSPECIFIED
Record Number:CaltechAUTHORS:20220816-183023896
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:116308
Deposited By: George Porter
Deposited On:16 Aug 2022 22:01
Last Modified:16 Aug 2022 22:01

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