Formation of polaron clusters

TL;DR

This paper investigates the formation of spherical polaron clusters within the Fröhlich polaron framework, identifying conditions under which polaron clusters form and assessing their stability in a dilute gas.

Contribution

It introduces a non-local statistical approach combined with Pekar strong coupling theory to analyze cluster formation and stability in polaron gases.

Findings

Homogeneous polaron phase is unstable to cluster formation.

Critical electron-phonon interaction values for bound states are determined.

Sequence of state filling and cluster stability are analyzed.

Abstract

The formation of spherical polaron clusters is studied within the Fr$\ddot{o}$hlich polaron theory. In a dilute polaron gas, using the non-local statistical approach and the polaron pair interaction obtained within the Pekar strong coupling theory, the homogeneous phase results to be unstable toward the appearance of polaron clusters. The physical conditions of formation for the clusters are determined calculating the critical values of electron-phonon interaction for which bound states in the collective polaron potential develop. Finally the sequence in the filling of the states is found and the stability of the clusters is assessed.