EFFICIENT TOOLS FOR THEORETICALLY INVESTIGATING SURFACE-STRUCTURE APPLIED TO AL ON GRAPHITE

Large-cluster calculations are used to investigate the surface structure of an Al atom on graphite. Experimentally direct images of an Al atom adsorbed vertically above a C atom have been observed with the scanning tunneling microscope. Similar surface structures are only obtained theoretically when substrate relaxation effects are included in the calculations. Cluster calculations which include the treatment of surface relaxation effects are computationally demanding and we demonstrate how our recently developed pseudo-lattice symmetry and partial optimization techniques make such calculations more tractable.