Screening of pair fluctuations in superconductors with coupled shallow and deep bands: a route to higher temperature superconductivity

L. Salasnich; A. A. Shanenko; A. Vagov; J. Albino Aguiar; A. Perali

doi:10.1103/physrevb.100.064510

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arXiv · 1810.03321

Screening of pair fluctuations in superconductors with coupled shallow and deep bands: a route to higher temperature superconductivity

L. Salasnich·A. A. Shanenko·A. Vagov·J. Albino Aguiar·A. Perali

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Abstract

A combination of strong Cooper pairing and weak superconducting fluctuations is crucial to achieve and stabilize high-Tc superconductivity. We demonstrate that a coexistence of a shallow carrier band with strong pairing and a deep band with weak pairing, together with the Josephson-like pair transfer between the bands to couple the two condensates, realizes an optimal multicomponent superconductivity regime: it preserves strong pairing to generate large gaps and a very high critical temperature but screens the detrimental superconducting fluctuations, thereby suppressing the pseudogap state. Surprisingly, we find that the screening is very efficient even when the inter-band coupling is very small. Thus, a multi-band superconductor with a coherent mixture of condensates in the BCS regime (deep band) and in the BCS-BEC crossover regime (shallow band) offers a promising route to higher critical temperatures.

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BibTeX RIS

L. Salasnich, A. A. Shanenko, A. Vagov, J. Albino Aguiar, A. Perali. 2019-02-20. Screening of pair fluctuations in superconductors with coupled shallow and deep bands: a route to higher temperature superconductivity. https://doi.org/10.1103/physrevb.100.064510

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