<i>Ab initio</i> based empirical potential applied to tungsten at high pressure

Abstract

Density-functional theory forces, stresses, and energies comprise a database from which the optimal parameters of a spline-based empirical potential combining Stillinger-Weber and modified embedded-atom forms are determined. The accuracy of the potential is demonstrated by calculations of ideal shear, stacking fault, vacancy migration, elastic constants, and phonons all between 0 and 100 GPa. Consistency with existing models and experiments is demonstrated by predictions of screw dislocation core structure and deformation twinning in a tungsten nanorod. Last, the potential is used to study the stabilization of fcc tungsten at high pressure.