Heat transport in Mo3Sb7 single crystal: Evidence for nodeless s-wave superconducting gap

•We present the resistivity and the thermal conductivity study of Mo3Sb7.•The residual linear term κ0/Tκ0/T is absent at zero field.•The field dependence of κ0/Tκ0/T evolves slowly in low fields.•The single crystal Mo3Sb7 has nodeless s-wave superconducting gap.

We investigate the superconducting gap structure of the intermetallic superconductor Mo3Sb7 single crystal by low-temperature thermal conductivity measurements. In zero field, the absence of a residual linear term κ0/Tκ0/T in the T→0T→0 limit provides strong evidence for nodeless superconducting gap. The field dependence of κ0/Tκ0/T is very similar to that of InBi, a typical s-wave superconductor in the dirty limit. These results demonstrate that Mo3Sb7 has nodeless s-wave superconducting gap, despite the opening of a spin gap at 53 K and the possible interplay between superconductivity and magnetism.