Orbital Selective Kondo Effect in Heavy Fermion Superconductor UTe$_{2}$

TL;DR

This study uses ab initio calculations to reveal orbital-selective Kondo effects in UTe$_{2}$, showing how different hybridizations lead to temperature-dependent resistivity behaviors and how pressure suppresses the Kondo effect.

Contribution

It provides a detailed ab initio analysis of the orbital-selective Kondo effect in UTe$_{2}$ without adjustable parameters, linking hybridization patterns to experimental observations.

Findings

U-5f electrons are highly localized, causing the Kondo effect.

Hybridization in the ab-plane leads to high-temperature Kondo behavior.

U-5f and Te-5p hybridization causes low-temperature resistivity upturn.

Abstract

It has been a great challenge to explore many-body effects in heavy fermion systems with $ab$-$initio$ approaches. We computed the electronic structure of UTe$_{2}$ without purposive judgements, such as intentional selection of on-site Coulomb interaction and disregarding spin-orbit coupling. We show that U-5$f$ electrons are highly localized in the paramagnetic normal state, giving rise to the Kondo effect. It is also found that the hybridization between U-5$f$ and U-6$d$ predominantly in the orthorhombic $ab$-plane is responsible for the high-temperature Kondo effect. In contrast, the hybridization between U-5$f$ and Te-5$p$ along the $c$-axis manifests the Kondo scattering at a much lower temperature, which could be responsible for the low-temperature upturn of the $c$-axis resistivity. Our results show that the electron correlation in UTe$_2$ is orbital selective, which naturally elucidates the recent experimental observations of anomalous temperature dependence of resistivity. Furthermore, we suggest that the Kondo effect is suppressed at high pressure owing to weak localization of magnetic moments, which results from enhanced U-5$f$ electron hopping.