Hydrostatic pressure studies on non-superconducting UTe2

TL;DR

This study investigates the pressure-temperature phase diagram of non-superconducting UTe2, revealing filamentary superconductivity without bulk transition and emphasizing the importance of complementary measurement techniques.

Contribution

It provides new insights into the inhomogeneity effects in UTe2 and demonstrates the necessity of multiple measurement methods to accurately identify bulk superconductivity.

Findings

Filamentary superconductivity observed at ambient pressure.

No evidence of bulk superconductivity up to 1.6 GPa.

Electrical resistivity alone can be misleading in detecting bulk superconductivity.

Abstract

We report the temperature-pressure phase diagram of a UTe$_2$ single crystal that does not undergo a bulk superconducting transition but shows filamentary superconductivity with a critical transition temperature of 1 K at ambient pressure. Electrical-resistivity measurements reveal that the evolution of the filamentary superconducting state under pressure resembles the behavior observed in previous reports on bulk superconducting samples. AC calorimetry, however, does not show evidence for either bulk superconductivity or magnetism for pressures up to 1.6 GPa. Our results highlight the role of inhomogeneity in chemical-vapor-transport-grown UTe$_2$ samples and serve as a cautionary tale when probing electrical resistivity alone.