A nonorthogonal-basis calculation of the spectral density of surface states for the (100) and (110) faces of tungsten

Abstract

The transfer matrix approach for the calculation of layer Green functions with a tight-binding Hamiltonian is extended to the case of a nonorthogonal basis. The problem can be rewritten in terms of an energy- and overlap-dependent pseudopotential. An application is made to the calculation of the spectral and total densities of states for the (100) and (100) faces of tungsten. Comparisons with calculations without overlap indicates that overlap effects do not play an important role except at the point Gamma of the (100) surface, where changes in the energy positions and the intensities of the peaks are found.