Investigation of electronic structure of disordered alloys

ABSTRACT MASTER THESIS INVESTIGATION OF ELECTRONIC STRUCTURE OF DISORDERED ALLOYS F. Ahmet ÇELİK Firat University Graduate School of Science and Technology Department of Physics 2004, Page : 54 In this study, it is aimed to calculate the electronic density of states for an AXB!_X alloy model distributed on a square lattice in a two dimensional lattice according to a statistical order using Beeby&Hayes method, which was developed for structural disordered systems, based on the multiple scattering theory. In the study, first, the dynamic equations applicable to the model system are evaluated from the formal relations of the theoretical method. The possible distributions of patterns of the model system having 50% A and 50% B atomic concentrations on a square lattice are illustrated explicitly on diagrams. Though the model system appears on the diyagram like a substitutional disordered alloy, it is treated as a structural disordered one so that the structural factors need to be determined. As the result of twelve possible distributions on the lattice, a complex block matrix is obtained, which is then reduced to 48x48 hermitian block matrix. In the last step, the matrix reduced to a solvable form is evaluated for several structural factors such as concentrations and bond distances, and then the density of electronic states is calculated. Moreover, variation of the spectral function to the momentum is investigated. Keywords: Disordered systems, Multiple scattering, Density of states, Beeby&Hayes Method VII