Single-component superconducting state in UTe2 at 2 K

TL;DR

This study clarifies that high-quality UTe2 single crystals exhibit a single superconducting transition at 2 K, challenging previous claims of multicomponent superconductivity and providing insights into its intrinsic properties.

Contribution

The paper demonstrates that UTe2 single crystals with optimal T_c show a single transition, questioning the multicomponent superconductivity hypothesis at ambient pressure.

Findings

UTe2 crystals have a single superconducting transition at 2 K.

High-quality crystals show small residual heat capacity and large residual resistance ratio.

Results challenge the idea of multicomponent superconductivity in UTe2 at ambient pressure.

Abstract

UTe2 is a newly-discovered unconventional superconductor wherein multicomponent topological superconductivity is anticipated based on the presence of two superconducting transitions and time-reversal symmetry breaking in the superconducting state. The observation of two superconducting transitions, however, remains controversial. Here we demonstrate that UTe2 single crystals displaying an optimal superconducting transition temperature at 2 K exhibit a single transition and remarkably high quality supported by their small residual heat capacity in the superconducting state and large residual resistance ratio. Our results shed light on the intrinsic superconducting properties of UTe2 and bring into question whether UTe2 is a multicomponent superconductor at ambient pressure.