Tunneling spectra of unconventional quasi-two-dimensional superconductors

Fuente: arXiv
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Autores principales: Pisani, L., Moshe, A. G., Pieri, P., Strinati, G. Calvanese, Deutscher, G.
Formato: Preprint
Publicado: 2024
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author Pisani, L.
Moshe, A. G.
Pieri, P.
Strinati, G. Calvanese
Deutscher, G.
author_facet Pisani, L.
Moshe, A. G.
Pieri, P.
Strinati, G. Calvanese
Deutscher, G.
contents Superfluid condensation can fundamentally be different from that predicted by the Bardeen-Cooper-Schrieffer (BCS) theory. In a broad class of low-carrier-density superconductors, such as granular aluminum, doped nitrides, and high-Tc cuprates, tunneling experiments reveal strong rather than weak coupling, as well as a conductance that does not return to that of the normal state upon approaching the critical temperature Tc. Here, we show that this behavior is in quantitative agreement with a tunneling theory that takes into account the large pairing-fluctuation effects that occur in the crossover region from weak-coupling BCS to strong-coupling Bose-Einstein condensation, provided the coherence energy scale rather than the single-particle energy gap is used to evaluate the coupling ratio. We also propose that the tendency toward strong coupling is a generic property of quasi-2D low-carrier-density superconductors.
format Preprint
id arxiv_https___arxiv_org_abs_2409_16804
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Tunneling spectra of unconventional quasi-two-dimensional superconductors
Pisani, L.
Moshe, A. G.
Pieri, P.
Strinati, G. Calvanese
Deutscher, G.
Superconductivity
Quantum Gases
Superfluid condensation can fundamentally be different from that predicted by the Bardeen-Cooper-Schrieffer (BCS) theory. In a broad class of low-carrier-density superconductors, such as granular aluminum, doped nitrides, and high-Tc cuprates, tunneling experiments reveal strong rather than weak coupling, as well as a conductance that does not return to that of the normal state upon approaching the critical temperature Tc. Here, we show that this behavior is in quantitative agreement with a tunneling theory that takes into account the large pairing-fluctuation effects that occur in the crossover region from weak-coupling BCS to strong-coupling Bose-Einstein condensation, provided the coherence energy scale rather than the single-particle energy gap is used to evaluate the coupling ratio. We also propose that the tendency toward strong coupling is a generic property of quasi-2D low-carrier-density superconductors.
title Tunneling spectra of unconventional quasi-two-dimensional superconductors
topic Superconductivity
Quantum Gases
url https://arxiv.org/abs/2409.16804