Suppression of the Kondo Resistivity Minimum in Magnetic Topological Insulators

TL;DR

This paper investigates how spin-momentum locking in magnetic topological insulators suppresses the Kondo resistivity minimum, revealing a dominant phonon-induced resistivity behavior at temperatures above the Kondo temperature.

Contribution

It provides a theoretical analysis showing the suppression of the Kondo effect in magnetic topological insulators due to spin-momentum locking, with predictions of resistivity behavior.

Findings

Kondo temperature is suppressed by spin-momentum locking.

Resistivity is dominated by phonons with a T^4 dependence.

Kondo screening cloud formation is prevented in these materials.

Abstract

Magnetically-doped topological insulators are intensely studied in the search for exotic phenomena such as the quantum anomalous Hall effect. The interplay of electronic and impurity degrees of freedom leads to the Kondo effect, an increase in the resistivity at temperatures $T < T_K$, the Kondo temperature. We study this effect in chiral surface state transport at $T \ge T_K$ in the metallic regime, starting from the quantum Liouville equation and including Kondo scattering to all orders, as well as phonon and non-magnetic impurity scattering. Unlike spin-orbit coupled metals and semiconductors, $T_K$ is suppressed by spin-momentum locking which prevents the formation of a Kondo screening cloud. We expect a resistivity $\rho_{xx} \propto T^4$ primarily due to phonons.