Superconducting properties of a nonideal bipolaron gas

TL;DR

This paper models a Bose gas of bipolarons with short-range correlations to explain high-temperature superconductivity, calculating critical properties and suggesting ways to enhance critical temperatures.

Contribution

It introduces a nonideal bipolaron Bose gas model with short-range correlations, differing from BCS theory, and applies it to high-temperature superconductor experiments.

Findings

Calculated critical temperature and transition energy for bipolaron Bose gas.

Explained experimental data on high-temperature superconductors.

Discussed potential methods to increase critical temperature.

Abstract

The properties of a Bose gas of translation-invariant (TI) bipolarons analogous to Cooper pairs are considered. As in the BCS theory, the description of a TI-bipolaron gas is based on the electron-phonon interaction and Froehlich Hamiltonian. As distinct from the BCS theory, when the correlation length greatly exceeds the mean distance between the pairs, here we deal with the opposite case when the correlation length is much less than the distance between the pairs. We calculate the critical temperature of the transition of a TI-bipolaron Bose-gas into the superconducting state, its energy, heat capacity and heat of the transition. The results obtained are used to explain the experiments on high-temperature superconductors. Possible ways of raising the critical temperature of high-temperature superconductors are discussed.