Random Kondo Alloys

TL;DR

This paper investigates how disorder affects the Kondo effect in alloys using CPA and DMFT methods, revealing complex dependencies of Kondo and Fermi liquid temperatures on disorder and concentration.

Contribution

It introduces a matrix CPA approach to study disordered Kondo alloys and compares it with DMFT, providing new insights into disorder effects on Kondo physics.

Findings

Kondo and Fermi liquid temperatures show non-monotonous behavior with disorder.

The formalism agrees with DMFT results for Bethe lattice structures.

Disorder influences the Kondo effect in complex, non-linear ways.

Abstract

The interplay between the Kondo effect and disorder is studied. This is done by applying a matrix coherent potential approximation (CPA) and treating the Kondo interaction on a mean-field level. The resulting equations are shown to agree with those derived by the dynamical mean-field method (DMFT). By applying the formalism to a Bethe tree structure with infinite coordination the effect of diagonal and off-diagonal disorder are studied. Special attention is paid to the behavior of the Kondo- and the Fermi liquid temperature as function of disorder and concentration of the Kondo ions. The non monotonous dependence of these quantities is discussed.