Calculation of the energies of core structures of the ½〈111〉 screw dislocation in b.c.c. Mo by the tight-binding recursion method

Abstract

The tight-binding recursion method is used to investigate the structure of the screw dislocation core in the b.c.c. transition metal Mo. The short-range repulsive energy between adjacent atoms is described by a Born-Mayer potential and taken into account in the total energy calculation. It is shown that the stable core structure of the 1/2<111> screw dislocation is of non-degenerate unpolarized type. The physical reason for the relative stability of the non-degenerate core with respect to the degenerate core is discussed. The cut-off parameter r _c in the self-energy expression of the screw dislocation is calculated to be 0-32b, where b is the magnitude of the Burgers vector.