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J. Phys.: Condens. Matter 4 (1992) pp. 1475-1488

Full-potential embedding for surfaces and interfaces

S. Crampin, J.B.A.N. van Hoof, M. Nekovee and J.E. Inglesfield

Institute for Theoretical Physics, Catholic University of Nijmegen, Toernooiveld, NL-6525 ED Nijmegen, The Netherlands

Abstract
We extend the surface-embedded Green function technique for calculating the electronic structure of surfaces and interfaces by presenting a method for determining substrate embedding potentials which makes no approximations to the substrate potential. We first present an alternative derivation of the surface embedded Green function method, to clarify the use of a planar surface in simulating embeddeing on a more complicated surface, and illustrate this with rigorous tests. Considering the case of a region embedded on two surfaces, we determine the conditions under which the resulting Green function may itself be used as a substrate embedding potential, and thereby derive a precedure for obtaining anembedding potential which makes no approximation to the substrate potential. In the case of a substrate with semi-infinite preiodicity this reduces to a self-consistency relation, for which we describe a first-order iterative solution. Finally, a particularly efficient scheme for obtaining local properties within a surface or interface region is outlined. This constitutes a full-potential solution to the one-electron Schrödinger equation for systems of two-dimensional periodicity, whose calculation time scales linearly with the number of atomic planes.