Coexistence of superconductivity and charge density wave in a correlated regime

TL;DR

This paper explores how superconductivity and charge density waves can coexist in a correlated electronic system, analyzing the effects of interactions, hopping, and temperature using Green's functions and Hubbard-I approximation.

Contribution

It introduces a theoretical framework combining Green's functions and Hubbard-I approximation to study coexistence of superconductivity and CDW with correlated electrons.

Findings

Small second-nearest neighbor hopping promotes coexistence.

Increasing hopping reduces competition between phases.

Temperature influences the stability of the coexistence regime.

Abstract

To investigate the coexistence of superconductivity and charge density wave (CDW) in a correlated regime, we employ the Green's functions formalism, as well as the Hubbard-I approximation, as a way to introduce the correlations into the problem, in the form of a repulsive Coulomb interaction $U$. In addition, we investigate the effects of second-nearest neighbor hopping $t_1$ on a pure CDW state. The analysis of the results show that, for small values of $t_1$, both CDW and superconducting gaps compete for the same region on the Fermi surface. The increase of $t_1$ decreases the competition and may lead the system to a coexistence regime. Effects of temperature in the coexistence regime, are also investigated.