Field-direction sensitivity of Kondo hybridization in UTe$_2$

TL;DR

This study investigates how magnetic fields along the a-axis affect Kondo hybridization in UTe₂, revealing a field-induced change in electron hybridization near 7 T through neutron scattering and resistivity measurements.

Contribution

It provides new insights into the field-direction sensitivity of Kondo hybridization in UTe₂, highlighting a specific field-induced change near 7 T.

Findings

Inelastic neutron spectral weight increases with field up to 13 T.

A pronounced change in spectral response near 7 T.

Field-induced modification of f-electron hybridization.

Abstract

Neutron scattering experiments on the spin-triplet superconductor UTe$_2$ have established that the dominant low-energy magnetic response is along Brillouin zone boundaries, resembling the magnetic susceptibility of narrow-gap interband excitations. We report a study of the sensitivity of these excitations to magnetic field along the crystallographic $\hat{a}$-axis. Up to fields of $\mu_0 H$=13 T, the maximal inelastic neutron spectral weight increases in energy transfer, with a pronounced increase in $d\hbar\omega_{peak}/dH$ near $\mu_0 H$=7 T. This behavior parallels the field and temperature dependent features of the electrical resistivity that are associated with Kondo hybridization. Our measurements suggest that $\hat{a}$-axis fields near $\mu_0 H$=7~T induce a change in the hybridization between heavy $f$-electrons and the bare conduction band.