Unconventional superconducting properties of noncentrosymmetric Re5.5Ta

Abstract

Rhenium based noncentrosymmetric superconductors crystallizing in $\alpha$-Mn structure have become potential candidates to exhibit an unconventional superconducting ground-state. Here we report a detailed investigation on the superconducting and normal state properties of Re${}_{5.5}$Ta, that also has the $\alpha$-Mn structure. Magnetization, specific heat, and transport measurements confirm the bulk superconducting transition \textit{T}${}_C$ at 8.0 K. Upper critical field value (H${}_{C2}$(0)) calculated from magnetization, specific heat and AC transport measurements exceed the Pauli paramagnetic limit (14.7 T), indicating that the superconducting properties of Re${}_{5.5}$Ta are probably unconventional in nature. However, low-temperature specific heat and transverse-field muon spin rotation measurements suggest a surprising nodeless isotropic superconducting gap, although with strong electron-phonon coupling.

10 Pages, 7 Figures Accepted: Physical Review B

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Cited by in corpus (2)

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• Time-reversal symmetry breaking in Re-based superconductors: Recent developments