Prediction of Lattice Constants of some Transition Metal Nitrides using Different Functionals and Pseudo-potentials

Abstract

Properties of materials are best analyzed when lattice parameters of such compounds of materials are predicted accurately. In density functional theory prediction of lattice parameters, density functionals play important role in obtaining accurate values. In this study, density functional theory was used to investigate accurate prediction of lattice parameters of some transition metal nitrides. Local Density Approximation (LDA) and Generalized Gradient Approximation of Perdew-Burke-Ernzerhof revised for solids (GGA-PBEsol) functionals combined with ultrasoft and projector augmented wave (PAW) pseudo-potentials were used for the investigation. The results indicated that GGA-PBEsol functional with PAW pseudo-potential performed better in predicting lattice parameters of these compounds. ForFeN compound, the calculated lattice parameter with GGA-PBEsol functional and PAW pseudo-potential was 4.232 Å compared with the experimental values of 4.307 Å and 4.296 Å corresponding to a little underestimation of about 1.74% and 1.49% respectively. Ultrasoft pseudo-potential of GGA-PBEsol functional and LDA functional with the two pseudo-potentials overestimated the lattice parameters for over 5%. It was concluded that, for the functionals and pseudo-potentials considered, GGA-PBEsol with PAW pseudo-potential may be a very good choice for prediction of lattice parameters of binary compounds with transition metals.