Atomic forces in the self‐consistent tight‐binding model

Abstract

AbstractThe self‐consistent tight‐binding (SCTB) model for structural and electronic properties of solids, which can treat both ionicity and covalency on an equal footing, is re‐formulated so as to be applicable to general and disordered systems and is analyzed in comparison with the tight‐binding bond (TBB) model. It is shown that atomic forces in the SCTB model are given very simply as well as in other tight‐binding type theories. Atomic forces consist of three types of contributions, which are those from the interatomic Coulomb interaction, from the covalent energy, and from the overlap repulsion. By using the present formulation, it is possible to calculate quantum‐mechanically the structural and electronic properties of extended defects or disordered systems of sp‐bondod materials with both the properties, ionicity and covalency, which have not yet been treated enough theoretically or quantitatively.