Numerical study of the $E\otimes e$ Jahn-Teller polaron and bipolaron

TL;DR

This study numerically examines the properties of Jahn-Teller polarons and bipolarons in one dimension, revealing similarities to Holstein polarons and highlighting differences in optical conductivity at strong coupling.

Contribution

It introduces a variational method to compute ground-state and dynamical properties of Jahn-Teller polarons and bipolarons, providing new insights into their behavior and differences from Holstein models.

Findings

Jahn-Teller and Holstein polarons are similar in some aspects.

Distinct differences in optical conductivity emerge at strong coupling.

Electron-phonon coupling and repulsion significantly affect bipolaron properties.

Abstract

The properties of the polaron and bipolaron are explored in the 1D Jahn-Teller model with dynamical quantum phonons. The ground-state properties of the polaron and bipolaron are computed using a recently developed variational method. Dynamical properties of the ground state of a polaron are investigated by calculating the optical conductivity $\sigma(\omega)$. Our numerical results suggest that the Jahn-Teller and Holstein polarons are similar. However, in the strong-coupling regime qualitative differences in $\sigma(\omega)$ between the two models are found and discussed. The influence of the electron-phonon coupling and the electrostatic repulsion on the bipolaron binding energy, bipolaron masses, and correlation functions is investigated.