Abstract
A set of density-functional calculations for clean and O-covered Al(111) are presented. At low O coverages the potential energy surface (PES) of chemisorbed O is investigated. The PES indicates large barriers (0.8 eV) against O diffusion and a large corrugation of the equilibrium O height over the Al(111) while only a moderate energy gain (5 eV per atom) is found upon Oz dissociation over the surface. The possible existence of ''hot'' O adatoms after O-2 dissociation is discussed on the basis of the presented PES and existing dynamical simulations on model potentials. At high O coverages an attractive O-O interaction is identified together with an enhancement in the dipole moment induced per O atom. Finally, Tersoff-Hamann-type scanning tunneling microscopy (STM) topographs are derived based on the calculated one-electron wave functions and spectra. For the clean Al(111) a theoretical STM height corrugation compatible with the experimentally observed one is obtained if the tunneling conductance is assumed dominated by contributions from orbitals of atomic p character centered on the tip. For the O-covered Al(111) the theoretical topographs agree well with the observed ones.
Original language | English |
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Journal | Physical Review B |
Volume | 52 |
Issue number | 20 |
Pages (from-to) | 14954-14962 |
ISSN | 2469-9950 |
DOIs | |
Publication status | Published - 1995 |
Bibliographical note
Copyright (1995) American Physical Society.Keywords
- ALUMINUM 111
- METAL-SURFACES
- CHEMISORPTION
- AL
- PHOTOELECTRON-SPECTROSCOPY
- PHOTOEMISSION
- SCANNING-TUNNELING-MICROSCOPY
- OXIDATION
- CLUSTER-MODEL
- SITE DETERMINATION