Complex surface reconstructions solved by ab initio molecular dynamics

G. Kresse1, W. Bergermayer2, R. Podloucky2, E. Lundgren3, R. Koller4, M. Schmid4, P. Varga4

1Institut für Materialphysik, Universität Wien & Center for Computational Materials Science, Universität Wien, A 1090 Wien, Austria
2Institut für Physikalische Chemie, A 1090 Wien, Austria
3Department of Synchrotron Radiation Research, Institute of Physics, University of Lund, Box 118, 22100 Lund, Sweden
4Institut für Allgemeine Physik, Technische Universität Wien, A 1040 Wien, Austria

Appl. Phys. A 76 (2003) 701-710

Complex surface reconstructions and surface oxides, in particular, often exhibit complicated atomic arrangements, which are difficult to resolve with traditional experimental methods, such as low energy electron diffraction (LEED), surface X-ray diffraction (SXRD) or scanning tunnelling microscopy (STM) alone. Therefore, ab initio density functional calculations are used as a supplement to the experimental techniques, but even then the structural determination usually relies on a simple trial and error procedure, in which conceivable models are first constructed and then tested for their stability in ab initio calculations. An exhaustive search of the configuration space is usually difficult and requires a significant human effort. Solutions to this problem, such as simulated annealing, have long been known, but are usually considered to be too time-consuming in combination with first principles methods. In this work, we show that ab initio density functional codes are now sufficiently fast to perform extensive finite temperature molecular dynamics. The merits of this approach are exemplified for two cases, for a complex two-dimensional surface oxide on Pd(111), and for the oxygen induced c(6x2) reconstruction of V(110).

Corresponding author: G. Kresse. Reprints also available from M. Schmid (schmid< encoded email address >).

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