Comments on transition metal surface calculations

Abstract

The authors perform the first calculation of the surface density of states of a transition metal using the continued fraction method of Haydock, Heine and Kelly (1972) and including s and p basis functions along with the d orbitals. The need for the s and p basis functions in order to obtain hybridisation effects in the surface density of states is discussed, as well as the error inherent in using s and p atomic orbitals to represent nearly-free-electron states. Different surface potential shifts are shown to be needed to obtain surface charge neutrality in ferromagnetic and paramagnetic iron. The utility of the continued fraction method is compared with standard thin film k space methods.