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 |
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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 |
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dc.relation.ispartofseries |
Physical Review B 45 (1992), Nr. 4 |
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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 |
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dc.bibliographicCitation.volume |
45 |
|
dc.bibliographicCitation.firstPage |
1869 |
|
dc.description.version |
publishedVersion |
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tib.accessRights |
frei zug�nglich |
|