First Principle Investigation of Electronic, Transport, and Bulk Properties of Zinc-Blende Magnesium Sulfide

We have studied electronic, structural, and transport properties of zinc-blende magnesium sulfide (zb-MgS). We employed a local density approximation (LDA) potential and the linear combination of atomic orbitals (LCAO) method. Our computational method is able to reach the ground state of a material, as dictated by the second theorem of density functional theory (DFT). Consequently, our findings have the physical content of DFT and agree with available, corresponding experimental ones. The calculated band gap of zb-MgS, a direct gap equal to 4.43 eV, obtained at the experimental lattice constant of 5.620 Å, completely agrees with the experimental band gap of 4.45 ± 0.2 eV. We also report total (DOS) and partial (pDOS) densities of states, electron and hole effective masses, the equilibrium lattice constant, and the bulk modulus. The calculated pDOS also agree with the experiment for the description of the states at the top and the bottom of the valence and conduction bands, respectively

First-Principles Investigation of Electronic and Related Properties of Cubic Magnesium Silicide (Mg₂Si)

We present results from ab initio, self-consistent calculations of electronic, transport, and bulk properties of cubic magnesium silicide (Mg2Si). We employed a local density approximation (LDA) potential to perform the computation, following the Bagayoko, Zhao, and Williams (BZW) method, as improved by Ekuma and Franklin (BZW-EF). The BZW-EF method guarantees the attainment of the ground state as well as the avoidance of over-complete basis sets. The ground state electronic energies, total and partial densities of states, effective masses, and the bulk modulus are investigated. As per the calculated band structures, cubic Mg2Si has an indirect band gap of 0.896 eV, from Γ to X, for the room temperature experimental lattice constant of 6.338 Å. This is in reasonable agreement with the experimental value of 0.8 eV, unlike previous ab initio DFT results of 0.5 eV or less. The predicted zero temperature band gap of 0.965 eV, from Γ to X, is obtained for the computationally determined equilibrium lattice constant of 6.218 Å. The calculated value of the bulk modulus of Mg2Si is 58.58 GPa, in excellent agreement with the experimental value of 57.03 ± 2 GPa