Nodeless superconductivity in quasi-one-dimensional Nb2PdS5: A μsR study

Abstract

Muon spin relaxation and rotation (μSR) measurements have been performed to study the superconducting and magnetic properties of Nb2PdS5. Zero-field μSR data show that no sizable spontaneous magnetization arises with the onset of superconductivity in Nb2PdS5, which indicates that the time-reversal symmetry is probably preserved in the superconducting state of this system. A strong diamagnetic shift is observed in the transverse-field μSR data practically ruling out a dominant triplet-pairing superconducting state in Nb2PdS5. The temperature dependence of magnetic penetration depth evidences the existence of a single s-wave energy gap Δ(0) with a gap value of 1.07(4) meV at zero temperature. The ratio Δ(0)/kBTc=2.02(9) indicates that Nb2PdS5 should be considered as a moderately strong-coupling superconductor. The magnetic penetration depth at zero temperature is 785(20) nm, indicating a very low superfluid density consistent with the quasi-one-dimensional nature of this system.