Time-reversal symmetry breaking in noncentrosymmetric superconductor Re6Hf:further evidence for unconventional behaviour in the alpha-Mn family of materials

TL;DR

This paper reports the discovery of time-reversal symmetry breaking and unconventional superconductivity in Re6Hf, a member of the Re6X family, highlighting their significance in advancing superconductor research.

Contribution

It provides experimental evidence of unconventional behavior and time-reversal symmetry breaking in Re6Hf, expanding the understanding of the Re6X superconductor family.

Findings

Time-reversal symmetry breaking observed in Re6Hf

Superfluid density shows s-wave superconductivity

Re6X family identified as a new group of unconventional superconductors

Abstract

The discovery of new families of unconventional superconductors is important both experimentally and theoretically, especially if it challenges current models and thinking. By using muon spin relaxation in zero-field, time-reversal symmetry breaking has been observed in Re6Hf. Moreover, the temperature dependence of the superfluid density exhibits s-wave superconductivity with an enhanced electron-phonon coupling. This, coupled with the results from isostructural Re6Zr, shows that the Re6X family are indeed a new and important group of unconventional superconductors.