The effect of electron-electron interactions on the conditions of existence of a surface state

Electronic surface states in one-dimensional two-band tight-binding approximation model are studied using the Green function method. The local density of states at successive atoms in a semi-infinite chain, even in the case of atoms distant from the surface, is found to be clearly different from that observed in an unperturbed (infinite) chain. The surface atom occupancy is calculated self-consistently, with the effect of electron–electron interactions taken into account. The electron–electron interactions are shown to have a significant impact on the conditions of existence of surface states.