Self-consistent electronic structure of semi-infinite Si(001) (2×1) and Ge(001) (2×1) with model calculations for scanning tunneling microscopy

Abstract

We have investigated surface electronic properties of semi-infinite Si(001) (2×1) and Ge(001) (2×1) using our recently developed self-consistent scattering theoretical method. The calculations are based on local density functional formalism and make use of one-particle Green’s functions. We present results for both symmetric and asymmetric dimer reconstructions of the surfaces to contribute to the current discussion of their structural properties. From comparing our results with photoemission and inverse photoemission data, we find that the asymmetric dimer model agrees better with the data than the symmetric dimer model. These findings are discussed, as well, in light of the recent scanning tunneling microscopy data of Hamers et al. In particular, we use our theory to add to the interpretation of scanning tunneling microscopy and spectroscopy data on Si and Ge(001) (2×1) surfaces.