Quenched randomness, thermal fluctuations and reentrant superconductivity: application to UTe$_2$

Abstract

Reentrant superconductivity has been observed in the candidate spin-triplet superconductor UTe2 as a function of the magnetic field applied along the hard axis. Resistivity measurements have shown, a broadened superconducting transition appears near the minimal Tc, highlighting the importance of superconducting fluctuations in this regime. We present a phenomenological study assuming a field-driven first-order transition between two superconducting states. We show that with quenched randomness, inhomogeneity-enhanced superconducting fluctuations near the transition could naturally account for both the reentrant superconductivity as well as the broadened superconducting transition.