Field-angle dependence of magnetoresistance in UTe2

TL;DR

This study theoretically investigates the angle-dependent magnetoresistance in the normal state of UTe2, revealing Fermi surface warping effects and their influence on transport properties, aligning well with experimental observations.

Contribution

It provides a detailed theoretical analysis of angle-resolved magnetoresistance in UTe2, highlighting the role of Fermi surface geometry and band-dependent relaxation times.

Findings

Fermi surfaces are quasi-two-dimensional with warping in the $k_z$ direction.

Magnetoresistance oscillates with field tilt due to Fermi surface geometry.

Calculated results agree with recent transport experiments.

Abstract

We theoretically study angle-resolved magnetoresistance under rotated magnetic field in the normal state of a spin-triplet superconductor UTe$_2$. The Wannier model derived from a GGA+$U$ calculation shows quasi-two-dimensional Fermi surfaces with warping in the $k_z$ direction, consistent with quantum oscillation measurements in the high magnetic field regime. Solving the semiclassical Boltzmann equation, we show that the Fermi surface geometry gives rise to oscillations in the magnetoresistance when the field is tilted from the $c$ axis toward the $a$ or $b$ axis. By assuming a band-dependent relaxation time, the calculated angle-resolved magnetoresistance is in good agreement with the recent transport experiment. This is direct evidence for the warped Fermi surface revealed by ordinary intraband transport. It suggests that the hole band with long relaxation time dominates electron transport. The field angle dependence of the Hall resistivity is calculated for further experimental verification.