Surface states of a semi-infinite s-p hybrid diatomic linear chain

Abstract

The electronic densities of states of a semi-infinite diatomic linear chain consisting of atoms with two s-p hybrid orbitals have been studied by using the Green function method. We observed that there might exist one surface state within each of the three energy gaps associated with the s-p hybrid diatomic chain. Since these surface states appeared in the absence of any surface potential perturbation, they cannot be classified as Tamm states. Furthermore, as some of these surface states persisted even in the atomic limit, neither can they be identified as Shockley states. A systematic study of the nature of this new type of surface state has been carried out in detail.