s-Wave superconductivity in non-centrosymmetric Re_3W probed by magnetic penetration depth

TL;DR

This study investigates the magnetic penetration depth in non-centrosymmetric Re_3W superconductor, finding it consistent with conventional s-wave BCS theory and showing no signs of unconventional pairing.

Contribution

First measurement of mbda(T) in Re_3W using two techniques, confirming conventional s-wave superconductivity despite lack of inversion symmetry.

Findings

mbda(T) fits weak-coupling BCS s-wave model

No evidence of unconventional pairing due to inversion symmetry absence

Superconducting gap ratio elta(0)/k_B T_C=1.76

Abstract

We report measurements of the temperature dependence of the magnetic penetration depth \lambda(T) in non-centrosymmetric superconductor Re_3W. We employed two experimental techniques: extraction of \lambda(T) from magnetic {\em dc}-susceptibility, measured on a powder sample, and the rf tunnel diode resonator technique, where a bulk polycrystalline sample was used. The results of both techniques agree: the temperature dependence of the penetration depth can be well described by weak-coupling, dirty-limit, s-wave BCS theory where we obtain $\Delta(0)/k_BT_C=1.76$. No evidence for unconventional pairing resulting from the absence of the inversion symmetry is found.