Large Bipolaron in a Polaron-Gas Background

TL;DR

This paper investigates the stability of large bipolarons within a polaron gas, revealing that Fermi statistics can stabilize bipolarons, while exchange interactions tend to destabilize them, using Hartree-Fock calculations in 2D and 3D systems.

Contribution

The authors derive a criterion for bipolaron stability in a polaron gas and perform numerical analysis in both 2D and 3D using the Hartree-Fock approximation.

Findings

Polaron gas surroundings can stabilize large bipolarons due to Fermi statistics.

Exchange interactions tend to destabilize bipolarons.

Stability analyzed in both bulk and thin film geometries.

Abstract

A criterion, proposed by the present authors, is used to derive numerical results for the stability of a large bipolaron embedded in a polaron gas. The main conclusion is that an isolated metastable bipolaron can be stabilized by the polaron gas surroundings because of the Fermi statistics of polarons. On the other hand, it is found that the exchange interaction tends to destabilize the bipolaron. The study is performed both for bulk (3D) materials and for thin (2D) films within the Hartree-Fock approximation. The bipolaron is described by an extension of the Feynman