Atomic slide puzzle: self-diffusion of an impure atom.
In a series of recent papers [Phys. Rev. Lett. 86, 1562 (2001); Nature (London) 408, 665 (2000)] van Gastel and co-workers have presented what may be the first experimental evidence, based on a series of scanning tunnel microscope images, that impure, Indium atoms, embedded into the first, close-packed layer of a Cu(001) surface, are not localized but make concerted, long excursions. Such excursions occur due to continuous reshuffling of the surface following the position exchanges of both impure and host Cu atoms with the naturally occurring surface vacancies. van Gastel and co-workers have also formulated an original lattice-gas type model with asymmetric exchange probabilities, whose numerical solution is in a good agreement with the experimental data. In this paper we propose an exact lattice solution of several versions of this model.
Bénichou
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Laboratoire de Physique de la Matière Condensée, Collège de France, 11 place M. Berthelot, 75231 Paris Cedex 05, France.
Oshanin
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