Communication: Van der Waals corrections for an improved structural description of telluride based materials

Abstract

Density functional theory (DFT), using the generalized gradient approximation, fails to reproduce the structure of liquid tellurides, which manifests by an overestimation of the interatomic bond distances. Here, we take into account dispersion forces in a semi-empirical way and apply such DFT simulations to liquid Ge15Te85. Substantial improvement of the simulated structure factor and pair distribution function is found, together with a change in the diffusion constant. A detailed analysis shows that such dispersion forces strongly affect the local geometry and first coordination shell of the atoms, whereas angular distributions remain unchanged. © 2013 American Institute of Physics.