Modeling the diffusion of atoms in multicomponent semiconductors in a disordered state

Density functional theory (DFT) using the generalized gradient approximation (GGA) made it possible to optimize the crystal structure, calculate the lattice parameters and band structure of TlMS₂ (M = Ga, In) semiconductor compounds with a monoclinic structure (space group С2/с, No. 15). DFT calculations of the structure of compounds were expanded using two exchange-correlation functionals GGA-PBE and GGA + U (U is the Coulomb parameter) with a value of U – J = 2.1 eV (effective interaction parameter). Thermal diffusion coefficients (Dα) of atoms of individual types (α), i.e. atoms of thallium, gallium, indium and sulfur near the melting point of the compound were calculated by the molecular dynamics (MD) method. The values of atoms were obtained in the local neutrality approximation using the canonical MD ensemble. The values of the atoms were corrected to take into account the root-mean-square displacements of the atoms at a given time and temperature. The dependences Dα = f(1 / T) of atoms, described by the Arrhenius law, were constructed. The activation energy of atomic diffusion was calculated.