Minimum energy 2D patterns of atoms adsorbed on a hexagonal lattice
We obtain the lowest energy 2D arrangements of atoms adsorbed on a hexagonal lattice, assuming rational coverage and a repulsive dipolar adsorbate-adsorbate interaction. To this end we exhaustively explore the ordered arrangements compatible with the coverage, including those that have multiatomic u...
| Autores: | , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 1996 |
| País: | México |
| Institución: | Universidad Nacional Autónoma de México |
| Repositorio: | Sistema de Información de la Facultad de Ciencias, UNAM |
| OAI Identifier: | oai:repositorio.fciencias.unam.mx:11154/2972 |
| Acceso en línea: | http://hdl.handle.net/11154/2972 |
| Access Level: | acceso abierto |
| Palabra clave: | Chemistry, Physical Physics, Condensed Matter adatoms alkali metals atom-solid interactions, scattering, diffraction equilibrium thermodynamics and statistical mechanics platinum single crystal surfaces transition metals |
| Sumario: | We obtain the lowest energy 2D arrangements of atoms adsorbed on a hexagonal lattice, assuming rational coverage and a repulsive dipolar adsorbate-adsorbate interaction. To this end we exhaustively explore the ordered arrangements compatible with the coverage, including those that have multiatomic unit cells. For some coverages (theta=1/3, 1/4 and 1/7) we find a well defined ground state, and for others a nearly infinite degeneracy related to the possibility of creating dense arrays of linear defects with a negligible energy cost. We compare our results with some experimental determinations of surface structures in alkali overlayers on fcc (111) and hcp (0001) metal faces. Except for those systems that form islands, we have found agreement between our predicted ground states and experiment. Furthermore, no ordered structures with the coverages of our near degenerate states have been observed. |
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