Effect of screening of the electron-phonon interaction on the temperature of Bose-Einstein condensation of intersite bipolarons

TL;DR

This paper investigates how screening of the electron-phonon interaction affects the Bose-Einstein condensation temperature of intersite bipolarons within an extended Holstein-Hubbard model, revealing that increased screening raises the condensation temperature.

Contribution

It introduces a study of the impact of Yukawa-type screened electron-phonon interactions on bipolaron condensation temperature, a novel aspect in the extended Holstein-Hubbard model.

Findings

Higher screening increases the Bose-Einstein condensation temperature.

Screened electron-phonon interaction modifies bipolaron properties.

First analysis of screening effects on bipolaron condensation temperature.

Abstract

Here we consider an interacting electron-phonon system within the framework of extended Holstein-Hubbard model at strong enough electron-phonon interaction limit in which (bi)polarons are the essential quasiparticles of the system. It is assumed that the electron-phonon interaction is screened and its potential has Yukawa-type analytical form. An effect of screening of the electron-phonon interaction on the temperature of Bose-Einstein condensation of the intersite bipolarons is studied for the first time. It is revealed that the temperature of Bose-Einstein condensation of intersite bipolarons is higher in the system with the more screened electron-phonon interaction.