Localized Electronic States near Dislocations in Transition Metals

This article outlines a model for calculating the localized states of a edge dislocation in Mo. The model used for the calculations is based on the multiple-scattering model (SCF-Xα-SW). The purpose of this investigation is (1) to determine changes in the electronic structure of the lattice near the core region of defects, where local changes in symmetry occur. How much does the electronic structure shift when one approaches a line defect from far away in the perfect region? (2) Several methods were developed to calculate the atomic configurations of defects by computer simulations. The influence of such procedures on the atomic positions was investigated. Several sets of positions were used to evaluate the sensitivity of electronic structure to interatomic distances. The highest occupied orbital energy level in the dislocated lattice is -0.441 Ry, while for the perfect lattice -0.531 Ry was found. This implies a small electronic field gradient around the dislocation line, and a corresponding redistribution of the electronic energies is obtained. The orbital energies show only a slight difference between the results obtained using atomic configurations determined by two computational procedures (0.002% of the total energy)