Short-range order in disordered transition metal oxides, carbides, and nitrides with the B1 structure

Abstract

A method has been proposed for the simulation of the atomic structure of disordered phases of nonstoichiometric transition metal oxides, carbides, and nitrides with the B1 structure taking into account the shortrange order in the arrangement of structural vacancies. The simplest structural models constructed with allowance for pair correlations between vacancies within the first four coordination spheres have been considered. A computer simulation of the atomic structure of disordered phases with the inclusion of the shortrange order has been performed. For each stru ctural model, the maximum possible concentration of vacancies and the shortrange order parameters at diffe rent concentrations have been calculated. For a fur� ther experimental verification, the influence of the shortrange order on the shape of the Xray scattering spectrum has been investigated by calculating the theoretical Xray diffraction patterns according to the Debye formula. The influence of the shortrange order on the total energy of the disordered phases has been analyzed by ab initio methods. It has been shown that, in some cases, the proposed structural models of the shortrange order are energetically favorable as compar ed to the model of statistical arrangement of vacan�