Kondo Effect in an Electron System with Dynamical Jahn-Teller Impurity

TL;DR

This paper explores how the Kondo effect arises in an Anderson model coupled with Jahn-Teller phonons, revealing phonon contributions to the singlet ground state and characterizing the Kondo temperature with an effective anisotropic s-d Hamiltonian.

Contribution

It demonstrates the role of dynamical Jahn-Teller phonons in the Kondo effect and derives an effective Hamiltonian to explain the characteristic temperature.

Findings

Total angular momentum is screened by conduction electrons.

Phonon degrees of freedom contribute to the singlet ground state.

Kondo temperature is explained by an effective anisotropic s-d Hamiltonian.

Abstract

We investigate how Kondo phenomenon occurs in the Anderson model dynamically coupled with local Jahn-Teller phonons. It is found that the total angular moment composed of electron pseudo-spin and phonon angular moments is screened by conduction electrons. Namely, phonon degrees of freedom essentially contribute to the formation of singlet ground state. A characteristic temperature of the Kondo effect due to dynamical Jahn-Teller phonons is explained by an effective $s$-$d$ Hamiltonian with anisotropic exchange interaction obtained from the Jahn-Teller-Anderson model in a non-adiabatic region.