Probing the superconducting ground state of the noncentrosymmetric superconductors CaTSi3 (T = Ir, Pt) using muon-spin relaxation and rotation

TL;DR

This study investigates the superconducting ground state of CaTSi3 (T=Ir, Pt) using muon spectroscopy, revealing preserved time-reversal symmetry and isotropic s-wave gaps, with detailed measurements of magnetic penetration depths and critical fields.

Contribution

It provides the first muon-spin relaxation and rotation analysis of CaTSi3 superconductors, characterizing their gap symmetry and magnetic properties.

Findings

Time-reversal symmetry is preserved in both materials.

Superfluid density fits isotropic s-wave gap model.

Quantitative magnetic penetration depths and critical fields are reported.

Abstract

The superconducting properties of CaTSi3 (where T = Pt and Ir) have been investigated using muon spectroscopy. Our muon-spin relaxation results suggest that in both these superconductors time-reversal symmetry is preserved, while muon-spin rotation data show that the temperature dependence of the superfluid density is consistent with an isotropic s-wave gap. The magnetic penetration depths and upper critical fields determined from our transverse-field muon-spin rotation spectra are found to be 448(6) and 170(6) nm, and 3800(500) and 1700(300) G, for CaPtSi3 and CaIrSi3 respectively. The superconducting coherence lengths of the two materials have also been determined and are 29(2) nm for CaPtSi3 and 44(4) nm for CaIrSi3.