AB INITIO CALCULATIONS OF THERMODYNAMIC PARAMETERS OF PbTe-SnTe SOLID SOLUTIONS

Abstract

Calculations of the equilibrium positions of atoms in clusters that had the dimensions of an elementary cell were made
due to density functional theory. Ab initio calculations of the crystal structure were performed and thermodynamic parameters
were determined for compounds based on PbTe with different Sn content from 15 to 85%. The modeling procedure consisted
of replacing of Lead atoms by Tin atoms in proportion to the investigated composition in their positions in the crystal lattice. A
decrease in the lattice constant with an increase in the contribution of Sn was observed. Thermodynamic parameters of
clusters with equilibrium positions of atoms were calculated for each chemical composition. Approximating equations for the
obtained curves were determined. Thermodynamic parameters show a regular change with temperature. The specific heat
capacity for the investigated compounds obeys the Debye and Dulong–Petit laws at appropriate temperatures.