Interplay between BCS and Mott physics in the phenomenon of high-$T_c$ superconductivity

TL;DR

This paper develops a modified BCS theory incorporating a Mott-like gap to better understand high-$T_c$ superconductivity in flat band systems, explaining the observed two-gap spectral features in underdoped cuprates.

Contribution

It introduces a new theoretical framework combining BCS and Mott physics to explain high-$T_c$ superconductivity in flat band materials.

Findings

Modified Gor'kov equations include a Mott-like gap.

The theory explains the two-gap structure in underdoped high-$T_c$ superconductors.

Insights into the interplay between Mott physics and superconductivity.

Abstract

Superconducting electron systems of solids hosting flat bands are studied, with a view to improved understanding of the fundamental physics giving rise to high-temperature superconductivity. We present a modified form of the set of Gor'kov equations of BCS theory that incorporates a Mott-like gap in the single-particle spectrum. Such a quantity is emergent in systems with flat bands having interactions repulsive in the Cooper channel, provided particle-hole symmetry is broken. The equations so obtained are applied to the elucidation of features of the two-gap structure of single-particle spectra of underdoped high-$T_c$ superconductors, as revealed in angle-resolved photoemission spectrometry.