We have performed a detailed theoretical study of the atomic geometry, electronic structure, and dispersion of the most tightly bound (n = 1) image state for the Si(111)-In(4 x 1) nanowire system. The calculations were performed using ab initio pseudopotentials, based on the local density approximation and a first-order energy correction for its asymptotic classical-image behaviour. The calculated atomic geometry, within the structural model proposed by Bunk et ai. Phys. Rev. B 59 (1999) 12228, agrees well with their X-ray diffraction studies, and the electronic band structure calculations confirm the quasi-one-dimensional semimetallic behaviour, in agreement with previous photoemission studies. The anisotropic dispersion of the image state measured in a recent inverse photoemission study by Hill and McLean Phys. Rev. Lett. 82 (1999) 2155 is verified, and an explanation based on the calculated surface corrugation potential is presented. (C) 2001 Elsevier Science B.V. All rights reserved. References: 31
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