Lattice dynamics study of lead chalcogenides

First principal calculations have been performed to study the structural and lattice-dynamical properties for lead chalcogenides compounds: PbS, PbSe and PbTe. The ground-states quantities such as the lattice parameter and bulk modulus were evaluated using the plane wave pseudo-potential method within the density-functional theory. Phonon dispersion spectra were derived from linear-response to density-functional theory. We have examined particularly the effect of pressure on the dynamical charges, longitudinal optical (LO), transverse optical (TO), and the splitting of LO-TO branches. The obtained results regarding dynamical properties under pressure have been confronted to the common III-V semiconductors. Finally thermodynamics quantities were reported by means of the quasiharmonic approximation. (C) 2010 Elsevier B.V. All rights reserved.