Superconductivity in ThMo2Si2C with Mo2C Square Net

We report the superconductivity of a new quaternary compound ThMo${}_2$Si${}_2$C, synthesized with the arc-melting technique. The compound crystallizes in a tetragonal CeCr${}_2$Si${}_2$C-type structure with cell parameters of $a$ = 4.2296 \r{A}and $c$ = 5.3571 \r{A}. 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 $\mathrm{\Delta }C\mathrm{/}{\gamma }_{\mathrm{n}}T$ = 0.98. The superconducting parameters of the critical magnetic fields, coherence length, penetration depth, and superconducting energy gap are given.