Superconductivity in non-centrosymmetric ThNiSi

Highlights: • ThNiSi is a bulk superconductor with Tc = 0.84 K. • The superconducting state has a type-II weakly-coupled BCS-like nature. • The upper critical field derived from the resistivity data shows an unusual temperature variation. We report on the synthesis of ThNiSi and the characterization of its physical properties by means of powder x-ray diffraction, magnetization, electrical resistivity and heat capacity measurements. The compound is confirmed to crystallize with a non-centrosymmetric tetragonal crystal structure of the LaPtSi-type (space group I4₁md). Below T_c = 0.85 K, it exhibits a BCS-type superconductivity with moderately anisotropic superconducting gap.