Electronic structure of a single MoS2 monolayer

The electronic structure of a single MoS₂ monolayer is investigated with all electron first-principles calculations based on Kohn Sham Density Functional Theory and variational treatment of spin-orbital coupling. The topologies of the valence band maximum and conduction band minimum are explored over the whole Brillouin zone. The single MoS₂ monolayer is confirmed to be a direct band gap semiconductor. The projected density of states (PDOS) of a single monolayer is calculated and compared to that of bulk MoS₂. The effective masses and the orbital character of the band edges at high-symmetry points of the Brillouin zone are determined. The spin-splittings of the conduction band minimum (CBMIN) and valence band maximum (VBMAX) are calculated over the whole Brillouin zone. It is found that the maximum spin-splitting of VBMAX is attained at the K point of the Brillouin zone and is responsible for the experimentally observed splitting between the A₁ and B₁ excitons.