Kondo effect in the presence of spin-orbit coupling

TL;DR

This paper investigates how spin-orbit coupling affects the Kondo effect in non-centrosymmetric metals, revealing that it can lead to unscreened magnetic moments and alter the Kondo energy, with implications for various materials.

Contribution

It introduces a variational approach to analyze the Kondo effect with arbitrary spin-orbit coupling in non-centrosymmetric metals, highlighting the impact on impurity screening.

Findings

Spin-orbit coupling can produce an unscreened impurity magnetic moment.

The Kondo energy can be significantly altered by spin-orbit interaction.

Implications for dilute impurities and heavy-fermion materials without inversion symmetry.

Abstract

We study the T=0 Kondo physics of a spin-1/2 impurity in a non-centrosymmetric metal with spin-orbit interaction. Within a simple variational approach we compute ground state properties of the system for an {\it arbitrary} form of spin-orbit coupling consistent with the crystal symmetry. This coupling produces an unscreened impurity magnetic moment and can lead to a significant change of the Kondo energy. We discuss implications of this finding both for dilute impurities and for heavy-fermion materials without inversion symmetry.