First-principles lattice dynamics ofNaCoO2

First-principles lattice dynamics and heat capacity of BiFeO3

We study the lattice dynamics of bismuth ferrite (BiFeO3) rhombohedral ferroelectric (R3c) using first-principles density functional theory calculations and the direct force constant method. We determine the phonon dispersions, phonon density of states, and heat capacity. Special attention is paid to the heat capacity at low temperature, at which the present phonon calculations show significant...

First-principles study of the lattice dynamics of K2SO4.

Using a newly developed first-principles approach to simulations of ionic molecular crystals, we performed static relaxation, molecular-dynamics simulation, and lattice-dynamics calculations, and measurements of the Raman spectrum, for the Pnam structure of K2SO4. It was found that the structure does not have the zone-center instability present in isomorphous K2SeO4 found in an earlier study. T...

First-principles study of the lattice dynamics of Sb2S3.

We present a lattice dynamics study of orthorhombic antimony sulphide (Sb2S3) obtained using density-functional calculations in conjunction with the supercell force-constant method. The effect of Born effective charges is taken into account using a mixed-space approach, resulting in the splitting of longitudinal and transverse optical (LO-TO) phonon branches near the zone center. Zone-center fr...

Lattice dynamics of anharmonic solids from first principles

First-principles lattice dynamics, thermodynamics, and elasticity of Cr2O3