Ab-initio Calculations of Electronic Properties of Bulk and 2D Molybdenum Disulfide (MoS₂)

We present results from ab-initio, self-consistent density functional theory (DFT) calculations of electronic properties of molybdenum disulfide (MoS₂), for the bulk and a 2D sample. The bulk MoS₂ (2H-MoS₂) is in the hexagonal structure with the space group P6₃/mmc and Pearson symbol hP6 (#194); the 2D sample is also in the hexagonal structure with the space group P-3m1. We utilized a local density approximation (LDA) potential and the linear combination of atomic orbital (LCAO) formalism. Our calculations performed a generalized minimization of the energy to reach the ground state, as required by the second DFT theorem. This process ensures the full, physical content of our findings that include electronic energy bands, total and partial densities of states, and electron and hole effective masses. Our calculated band gap for room temperature lattice constants of a= 3.16 Å and c=12.294 Å is 1.42 eV, for the bulk, and is indirect; it is 2.65 eV for the 2D samples, for lattice constants of a= 3.187 Å and c=31.87 Å, and is a direct band gap.