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Dramatically Enhanced Superconductivity in Elemental Bismuth from Excitonic Fluctuation Exchange.

ABSTRACT: Motivated by the remarkable discovery of superconductivity in elemental Bismuth at ambient pressure, we study its normal state in detail using a combination of tight-binding (TB) band-structure supplemented by dynamical mean-field theory (DMFT). We show that a two-fluid model composed of preformed and dynamically fluctuating excitons coupled to a tiny number of carriers provides a unified rationalization of a range of ill-understood normal state spectral and transport data. Based on these, we propose that resonant scattering involving a very low density of renormalized carriers and the excitonic liquid drives logarithmic enhancement of vertex corrections, boosting superconductivity in Bi. A confirmatory test for our proposal would be the experimental verification of an excitonic semiconductor with electronic nematicity as a 'competing order' on inducing a semi-metal-to semiconductor transition in Bi by an external perturbation like pressure.

SUBMITTER: Koley S

PROVIDER: S-EPMC5591209 | biostudies-literature | 2017 Sep

REPOSITORIES: biostudies-literature

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Dramatically Enhanced Superconductivity in Elemental Bismuth from Excitonic Fluctuation Exchange.

Koley S S Laad M S MS Taraphder A A

Scientific reports 20170908 1

Motivated by the remarkable discovery of superconductivity in elemental Bismuth at ambient pressure, we study its normal state in detail using a combination of tight-binding (TB) band-structure supplemented by dynamical mean-field theory (DMFT). We show that a two-fluid model composed of preformed and dynamically fluctuating excitons coupled to a tiny number of carriers provides a unified rationalization of a range of ill-understood normal state spectral and transport data. Based on these, we pr ...[more]

PMID: 28887558

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