First-principles calculations to investigate structural and mechanical properties of MoS2/MoSe2 vertical and lateral Superlattice

MoS2/MoSe2 superlattice is a potential candidate for thermoelectric materials. We have theoretically constructed MoS2/MoSe2 vertical and lateral superlattices based on the density functional theory. Here, five possible stacking structures of MoS2/MoSe2 vertical superlattice are considered. The optimized energy of AA1 structure is the lowest. The structural stability, electronic and mechanical properties of AA1 structure and lateral superlattice (LS) are studied. The results shows that AA1 and LS are thermodynamically, dynamically and mechanically stable. The calculated band structures display AA1 is an indirect bandgap semiconductor, while LS is a direct bandgap semiconductor. Furthermore, the sound speed of LS is slightly lower than that of AA1. The sound velocity of LS has a little anisotropy and is minimum in the [01] direction.