MAEAM simulation of phonons for BCC transition metals

Abstract

Combining MAEAM with the lattice dynamics, the atomic force constants and phonon dispersion curves have been obtained along five symmetry directions [0 0 ζ], [0 ζ ζ], [ ζ ζ ζ], [ 1 2 1 2 ζ ] and [ ζ ζ 1] for three BCC transition metals Ta, W and Mo within interactions out to the sixth neighbors. The calculated results that are nearly in agreement with available experimental results along [0 0 ζ], [0 ζ ζ] and [ ζ ζ ζ] directions implies that the predicted phonon dispersion curves along [ 1 2 1 2 ζ ] and [ ζ ζ 1] directions are well behaved. Along each symmetry direction, the vibration frequency that increases for Ta, W and Mo successively may be related to the ratio of cohesive energy E c to mass M.