Comparative study of the centrosymmetric and non-centrosymmetric superconducting phases of Re3W using muon-spin spectroscopy and heat capacity measurements

TL;DR

This study compares the superconducting properties of centrosymmetric and non-centrosymmetric Re3W using muon-spin spectroscopy and heat capacity measurements, revealing similar s-wave gap symmetry but differing critical temperatures and gap magnitudes.

Contribution

It provides the first detailed comparison of Re3W phases, showing both have s-wave superconductivity with different critical parameters and preserved time-reversal symmetry.

Findings

Both phases exhibit s-wave superconductivity.

CS phase has higher Tc and larger gap than NCS phase.

Both are strong-coupling superconductors.

Abstract

We compare the low-temperature electronic properties of the centrosymmetric (CS) and non-centrosymmetric (NCS) phases of Re3W using muon-spin spectroscopy and heat capacity measurements. The zero-field muSR results indicate that time-reversal symmetry is preserved for both structures of Re3W. Transverse-field muon spin rotation has been used to study the temperature dependence of the penetration depth lambda(T) in the mixed state. For both phases of Re3W, lambda(T) can be explained using a single-gap s-wave BCS model. The magnetic penetration depth at zero temperature, lambda(0), is 164(7) and 418(6) nm for the centrosymmetric and the non-centrosymmetric phases of Re3W respectively. Low-temperature specific heat data also provide evidence for an s-wave gap-symmetry for the two phases of Re3W. Both the muSR and heat capacity data show that the CS material has a higher Tc and a larger superconducting gap Delta(0) at 0 K than the NCS compound. The ratio Delta(0)/kBTc indicates that both phases of Re3W should be considered as strong-coupling superconductors.