Ab initio study of the fundamental properties of HgSe, HgTe and their HgSe_xTe_(1-x) alloys

摘要

First-principles calculations were performed to study the structural, electronic and thermodynamic properties of HgSe, HgTe and HgSe _xTe_(1-x) ternary alloys using the full potential-linearized augmented plane wave plus local orbitals method within the density functional theory. We use both the Wu-Cohen and Engel-Vosko generalized gradient approximations of the exchange-correlation energy that are based on the optimization of total energy and corresponding potential, respectively. Our investigation of the effect of composition on the lattice constant, bulk modulus and iconicity for ternary alloys shows almost nonlinear dependence on the composition. Besides, a regular-solution model is used to investigate the thermodynamic stability of the alloys, which mainly indicates a phase miscibility gap. In addition, the quasi-harmonic Debye model is used to determine the thermal properties of alloys up to 700 K.