Complex superconductivity in the noncentrosymmetric compound Re$_{6}$Zr

Abstract

We report the electronic structure, synthesis, and measurements of the magnetic, transport, and thermal properties of the polycrystalline noncentrosymmetric compound Re$_{6}$Zr. We observed a bulk superconducting transition at temperature $T_{c}$ $\sim$ 6.7 K, and measured the resistivity, heat capacity, thermal conductivity, and the London penetration depth below the transition, as well as performed doping and pressure studies. From these measurements we extracted the critical field, and the superconducting parameters of Re$_{6}$Zr. Our measurements indicate a relatively weak to moderate contribution from a triplet component to the order parameter, and favor a full superconducting gap, although we cannot exclude the existence of point nodes based on our data.