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Interplay between steps and nonequilibrium effects in surface diffusion for a lattice-gas model of O/W(110)

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dc.contributor Aalto-yliopisto fi
dc.contributor Aalto University en
dc.contributor.author Masin, M.
dc.contributor.author Vattulainen, Ilpo
dc.contributor.author Ala-Nissilä, Tapio
dc.contributor.author Chvoj, Z.
dc.date.accessioned 2015-04-21T09:00:49Z
dc.date.available 2015-04-21T09:00:49Z
dc.date.issued 2007
dc.identifier.citation Masin, M. & Vattulainen, I. & Ala-Nissilä, Tapio & Chvoj, Z. 2007. Interplay between steps and nonequilibrium effects in surface diffusion for a lattice-gas model of O/W(110). The Journal of Chemical Physics. Volume 126, Issue 11. 114705/1-8. 1089-7690 (electronic). 0021-9606 (printed). DOI: 10.1063/1.2713100. en
dc.identifier.issn 1089-7690 (electronic)
dc.identifier.issn 0021-9606 (printed)
dc.identifier.uri https://aaltodoc.aalto.fi/handle/123456789/15707
dc.description.abstract The authors consider the influence of steps and nonequilibrium conditions on surfacediffusion in a strongly interactingsurfaceadsorbate system. This problem is addressed through Monte Carlo simulations of a lattice-gas model of O∕W(110), where steps are described by an additional binding energy EB at the lower step edge positions. Both equilibrium fluctuation and Boltzmann-Matano spreading studies indicate that the role of steps for diffusion across the steps is prominent in the ordered phases at intermediate coverages. The strongest effects are found in the p(2×1) phase, whose periodicity Lp is 2. The collective diffusion then depends on two competing factors: domain growth within the ordered phase, which on a flat surface has two degenerate orientations [p(2×1) and p(1×2)], and the step-induced ordering due to the enhanced binding at the lower step edge position. The latter case favors the p(2×1) phase, in which all adsorption sites right below the step edge are occupied. When these two factors compete, two possible scenarios emerge. First, when the terrace width L does not match the periodicity of the ordered adatom layer (L/Lp is noninteger), the mismatch gives rise to frustration, which eliminates the effect of steps provided that EB is not exceptionally large. Under these circumstances, the collective diffusion coefficient behaves largely as on a flat surface. Second, however, if the terrace width does match the periodicity of the ordered adatom layer (L/Lp is an integer), collective diffusion is strongly affected by steps. In this case, the influence of steps is manifested as the disappearance of the major peak associated with the ordered p(2×1) and p(1×2) structures on a flat surface. This effect is particularly strong for narrow terraces, yet it persists up to about L≈25Lp for small EB and up to about L≈500Lp for EB, which is of the same magnitude as the bare potential of the surface. On real surfaces, similar competition is expected, although the effects are likely to be smaller due to fluctuations in terrace widths. Finally, Boltzmann-Matano spreading simulations indicate that even slight deviations from equilibrium conditions may give rise to transient peaks in the collective diffusion coefficient. These transient structures are due to the interplay between steps and nonequilibrium conditions and emerge at coverages, which do not correspond to the ideal ordered phases. en
dc.format.extent 114705/1-8
dc.format.mimetype application/pdf en
dc.language.iso en en
dc.publisher AIP Publishing en
dc.relation.ispartofseries The Journal of Chemical Physics en
dc.relation.ispartofseries Volume 126, Issue 11
dc.rights © 2007 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. http://scitation.aip.org/content/aip/journal/jcp en
dc.subject.other Physics en
dc.title Interplay between steps and nonequilibrium effects in surface diffusion for a lattice-gas model of O/W(110) en
dc.type A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä fi
dc.description.version Peer reviewed en
dc.rights.holder American Institute of Physics
dc.contributor.school Perustieteiden korkeakoulu fi
dc.contributor.school School of Science en
dc.contributor.department Department of Applied Physics en
dc.contributor.department Teknillisen fysiikan laitos fi
dc.subject.keyword diffusion en
dc.subject.keyword adsorption en
dc.subject.keyword collective models en
dc.subject.keyword Monte Carlo methods en
dc.subject.keyword strong interactions en
dc.identifier.urn URN:NBN:fi:aalto-201504212366
dc.type.dcmitype text en
dc.identifier.doi 10.1063/1.2713100
dc.type.version Final published version en

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