Low-temperature thermal conductivity of the noncentrosymmetric superconductor LaRhSi3

Abstract

We report on low-temperature thermal conductivity of the noncentrosymmetric superconductor LaRhSi3 (TC = 2.3K), which is a paramagnetic analog of the pressure-induced superconductor CeRhSi3. In the normal state (either in zero field above Tc, or in magnetic field above Hc2), the thermal conductivity k is mostly due to electrons, and shows a nearly T-linear dependence. In the superconducting state, k decreases exponentially below Tc, and crosses over to κ ∝ T2 behavior at T << Tc. The temperature dependence of thermal conductivity of LaRhSi3 is similar to that of a number of conventional s-wave superconductors. The field dependence of the residual linear term κ0/T as a function of magnetic field suggests that LaRhSi3 has no nodes in the superconducting gap.