Phase diagram and critical behavior of the adsorption system O/Ru(001): Comparison with lattice-gas models

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dc.identifier.uri http://dx.doi.org/10.15488/2798
dc.identifier.uri http://www.repo.uni-hannover.de/handle/123456789/2824
dc.contributor.author Piercy, P.
dc.contributor.author De'Bell, K.
dc.contributor.author Pfnür, Herbert
dc.date.accessioned 2018-02-19T14:57:19Z
dc.date.available 2018-02-19T14:57:19Z
dc.date.issued 1992
dc.identifier.citation Piercy, P.; De'Bell, K.; Pfnür, H.: Phase diagram and critical behavior of the adsorption system O/Ru(001): Comparison with lattice-gas models. In: Physical Review B 45 (1992), Nr. 4, 1869. DOI: https://doi.org/10.1103/PhysRevB.45.1869
dc.description.abstract The chemisorption of oxygen on the Ru(001) surface shows ordered p(2×2) and p(1×2) phases at coverages of 1/4 and 1/2 monolayer, respectively, that are observed to undergo apparently continuous transitions to a disordered state upon heating. We present here details of the experimental determination of the O/Ru phase diagram, lattice-gas models that describe it, and some (but not all) of the observed critical behavior. Monte Carlo simulations based on a phenomenological Hamiltonian describing pairwise interactions between adatoms are used to calculate the phase boundaries and (effective) critical exponents. Restricting adsorption of oxygen atoms to the triangular lattice of the hcp-type hollow sites as seen experimentally, repulsive first- and second-nearest-neighbor interactions are sufficient to describe the observed phase diagram at coverages Θ<0.4 and the four-state Pott’s-class critical exponents at Θ=1/4, but fail to describe the higher coverage region. This model is then generalized to allow oxygen adsorption on both hcp- and fcc-type hollow sites, with a difference in binding energy of 0.52 eV between the two types of sites. At higher coverages, repulsive interactions within the adsorbate lead to a spillover of up to 12% of adatoms onto the sites of higher energy, markedly reducing the transition temperature at Θ=1/2, in agreement with the experimental results on O/Ru(001). However, effective critical exponents computed for this model are near four-state Pott’s values at Θ=1/2, in contrast to the experimental data and suggestive of crossover behavior involving (2×2)-honeycomb and p(2×1) ground states. eng
dc.language.iso eng
dc.publisher College Park, MD : American Physical Society
dc.relation.ispartofseries Physical Review B 45 (1992), Nr. 4
dc.rights Es gilt deutsches Urheberrecht. Das Dokument darf zum eigenen Gebrauch kostenfrei genutzt, aber nicht im Internet bereitgestellt oder an Außenstehende weitergegeben werden.
dc.subject chemisorption eng
dc.subject oxygen eng
dc.subject Monte Carlo simulation eng
dc.subject.ddc 530 | Physik ger
dc.title Phase diagram and critical behavior of the adsorption system O/Ru(001): Comparison with lattice-gas models
dc.type article
dc.type Text
dc.relation.issn 01631829
dc.relation.doi https://doi.org/10.1103/PhysRevB.45.1869
dc.bibliographicCitation.issue 4
dc.bibliographicCitation.volume 45
dc.bibliographicCitation.firstPage 1869
dc.description.version publishedVersion
tib.accessRights frei zug�nglich


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