High Temperature Superconductivity from Strong Correlation

TL;DR

This paper investigates the potential for high-temperature superconductivity arising from strong electron correlations, emphasizing the roles of Coulomb interaction, exchange, and attractive interactions within a two-dimensional model.

Contribution

It demonstrates, using variational Monte Carlo, that high-temperature superconductivity can emerge from strongly correlated electron systems with specific interactions.

Findings

High U, J, and V interactions enhance superconductivity.

Strong correlations can lead to high T_c in the model.

Variational Monte Carlo confirms the cooperative effect of interactions.

Abstract

It is important to understand the mechanism of high-temperature superconductivity. It is obvious that the interaction with large energy scale is responsible for high critical temperature $T_c$. The Coulomb interaction is one of candidates that bring about high-temperature superconductivity because its characteristic energy is of the order of eV. There have been many works for the Hubbard model including three-band d-p model with the on-site Coulomb repulsion to investigate a possibility of high-temperature superconductivity. It is, of course, not trivial whether the on-site Coulomb interaction leads to a pairing interaction between two electrons. We argue that high-temperature superconductivity is possible in the strongly correlated region by using the variational Monte Carlo method for the two-dimensional t-U-J-V model. The exchange interaction J and the nearest-neighbour attractive interaction V cooperate with U and will act to enhance the critical temperature.