Kondo transport in an anisotropic two-dimensional electron gas with quadratic momentum-dependent spin splitting

TL;DR

This paper studies how quadratic spin textures in an anisotropic 2D electron gas affect Kondo scattering and transport, revealing a suppressed Kondo temperature and a critical coupling for Kondo collapse.

Contribution

It develops a Green's function framework to analyze the interplay between spin textures and Kondo effects in anisotropic 2D systems, highlighting the impact of quadratic spin-splitting.

Findings

Kondo temperature $T_K$ is strongly suppressed with increasing quadratic spin-splitting $oldsymbol{ extalpha}$.

Identifies a critical coupling $oldsymbol{ extalpha_{cr}}$ where Kondo collapse occurs.

$T_K$ is reduced by approximately 37% at the critical coupling compared to conventional 2D electron gases.

Abstract

We investigate the transport properties of an anisotropic two-dimensional electron gas with a quadratic spin texture, described by a low-energy effective $ k\cdot p$ model, in the presence of $S=1/2$ Kondo impurities. We develop a Green's function framework that captures the interplay between the spin texture and the Kondo scattering for calculating transport properties in such systems. Using this framework, we evaluate the longitudinal resistivity corrections $\Delta\rho^{xx}/\rho^{xx}_0$ and $\Delta\rho^{yy}/\rho^{yy}_0$ to third order in the $s$-$d$ exchange coupling and analyze their temperature dependence. We further determine the Kondo temperature $T_K$ and show that it is strongly suppressed with increasing quadratic spin-splitting coupling $\alpha$. In particular, we identify a critical coupling $\alpha_{cr}$ marking the onset of a Kondo collapse, at which $T_K$ is reduced by approximately 37\% relative to that of the conventional two-dimensional electron gas.