Multilayer relaxation of the Al(100) and Al(110) surfaces: An ab initio pseudopotential study

Abstract

The multilayer relaxations of Al(100) and Al(110) surface are studied using the plane wave ab initio pseudopotential method within the local density functional theory. Our calculations show that the surface relaxation of Al(100) is an `anomalous' outward relaxation, which is in excellent agreement with experimental results, although several previous empirical and semi-empirical theoretical studies have predicted contractions that are contrary to the experiments. For the Al(110) surface, our calculations do show inward relaxation, which is consistent with LEED experiments and other theoretical calculations. The origin of `inward' and `outward' relaxation is discussed. The surface energy is also studied in this work.