Theoretical Study of Impurity Effects on Superconductivity in UTe2

TL;DR

This theoretical study examines how impurities affect the superconducting transition temperature in UTe2, highlighting the importance of impurity site and magnetic properties in understanding pairing symmetry.

Contribution

It provides a detailed analysis of impurity effects on UTe2's superconductivity using a six-orbital model, emphasizing the role of impurity location and magnetic nature.

Findings

Impurities at U-sites significantly reduce Tc.

Magnetic impurities favor singlet pairing, non-magnetic favor triplet.

Impurity effects depend strongly on atom site and magnetic properties.

Abstract

This study investigates the impurity effects on UTe2 within the self-consistent Born approximation using the six-orbital f-d-p model which contains two uranium and tellurium atoms in the minimum unit cell. We analyze the dependence of superconducting transition temperature (Tc) on impurity concentration for various pairing symmetries proposed by experiments and theories. It clarifies that the decrease of Tc significantly depends on which atom sites the impurities reside. Particulalry, the analysis shows that the impurity at U-site has dominant effect on the change of Tc. Then, either the singlet state in the case of magnetic impurities or the triplet states in both non-magnetic and magnetic impurities are consistent with experiments. Thus, this indicates that elucidating the magnetic properties of impurities (i.e. magnetic or non-magnetic) is crucial for identifying the pairing symmetry of UTe2.