MODIFIED TIGHT-BINDING EQUATIONS FOR ELECTRON-WAVE FUNCTIONS IN CRYSTALS WITH POINT-DEFECTS

A system of tight-binding equations for the electron wave function in infinite, semi-infinite, or interface crystals with point defects is t ransformed to a finite system for the coefficients of specially constr ucted converging and diverging waves. The solution of this finite syst em allows the construction of the electron wave function over all spac e. This makes it possible to calculate the electronic structure of a d efect and its ''images'' in the various experimental methods used for studying defects in the bulk, on the surface, and at the interface of crystals, without conventional structural simplifications. The propose d method is applied to the calculation of point defects in a two-dimen sional square lattice.