“…14 Normconserving pseudopotentials for Sn, Ge, and S are generated with the APE pseudopotential generator. 15 The states treated as valence in Ge, Sn, and S were the 4s 2 4p 2 states, the 5s 2 5p 2 states, and the 3s 2 3p 4 states, respectively. For calculations on bulk SnS and GeS, the wavefunctions are expanded in plane waves with a kinetic energy cutoff of 50 Ry.…”