Superconductivity in ThMo2Si2C with Mo2C square net

We report the superconductivity of a new quaternary compound ThMo₂Si₂C, synthesized with the arc-melting technique. The compound crystallizes in a tetragonal CeCr₂Si₂C-type structure with cell parameters of a = 4.2296 Å and c = 5.3571 Å. An interlayer Si-Si covalent bonding is suggested by the atomic distance. The electrical resistivity and magnetic susceptibility measurements indicate a Pauli-paramagnetic metal with dominant electron-electron scattering in the normal-state. Bulk superconductivity at 2.2 K is demonstrated with a dimensionless specific-heat jump of ΔC/γ_nT = 0.98. The superconducting parameters of the critical magnetic fields, coherence length, penetration depth, and superconducting energy gap are given.