Modeling the Diffusion of Atoms in Multicomponent Semiconductors in a Disordered State

Abstract

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 \({\text{TlM}}{{{\text{S}}}_{2}}~\)(M = Ga, In) semiconductor compounds with a monoclinic structure (space group \(C2{\text{/}}c\), 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 (\({{D}_{\alpha }}\)) of atoms of individual types (α), i.e. atoms of thallium, gallium, indium and sulfur near the melting point of the \({\text{TlM}}{{{\text{S}}}_{2}}\) compound were calculated by the molecular dynamics (MD) method. The \({{D}_{\alpha }}\) values of \({\text{TlM}}{{{\text{S}}}_{2}}\) atoms were obtained in the local neutrality approximation using the canonical \(NVT\) MD ensemble. The \({{D}_{\alpha }}\) 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 \({{D}_{\alpha }} = ~f(1{\text{/}}T)\) of \({\text{TlM}}{{{\text{S}}}_{2}}\) atoms, described by the Arrhenius law, were constructed. The activation energy of atomic diffusion was calculated.