Charge Kondo anomalies in PbTe doped with Tl impurities

TL;DR

This paper demonstrates that the charge Kondo effect explains the unusual low-temperature and doping-dependent properties of Tl-doped PbTe, aligning well with experimental observations and offering new insights into the material's behavior.

Contribution

The study introduces a numerical renormalization group analysis showing the charge Kondo effect as the key mechanism in Tl-doped PbTe, providing a novel interpretation of experimental data.

Findings

Charge Kondo effect explains low-temperature anomalies.

Doping dependence matches experimental trends.

Spectral function analysis offers new insights.

Abstract

We investigate the properties of PbTe doped with a small concentration $x$ of Tl impurities acting as acceptors and described by Anderson impurities with negative onsite correlation energy. We use the numerical renormalization group method to show that the resulting charge Kondo effect naturally accounts for the unusual low temperature and doping dependence of normal state properties, including the self-compensation effect in the carrier density and the non-magnetic Kondo anomaly in the resistivity. These are found to be in good qualitative agreement with experiment. Our results for the Tl s-electron spectral function provide a new interpretation of point contact data.