FRENKEL-KONTOROVA DOMAIN-WALL PHASE-TRANSITIONS IN AN ADSORBED LAYER - POTASSIUM ON CO(10(1)OVER-BAR-0)

T MASUDA, CJ BARNES, P HU, DA KING

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Abstract

As the potassium fractional coverage of a cobalt {1010BAR} surface is increased over the range 0.2 to 0.6 monolayer the adlayer passes through a series of phase transitions. A commensurate phase is formed at exactly 0.5 monolayer, and corresponds to adatoms bonded in high-symmetry hollow sites on the unreconstructed cobalt surface, with an effective adatom radius lying between the ionic and covalent radii of potassium. A detailed structural study shows that the structural transitions can be characterised within a one-dimensional Frenkel-Kontorova model, with small lateral displacements of adatoms away from hollow sites in the low and high coverage phases. The low coverage phases progress from a distributed vacancy structure to a low density domain-wall structure; while the high coverage phase formed above half a monolayer is a high density asymmetric domain-wall structure.

Original languageEnglish
Pages (from-to)122-138
Number of pages17
JournalSurface Science
Volume276
Issue number1-3
Publication statusPublished - 01 Oct 1992

Keywords

  • SURFACE
  • CO(1010)
  • LEED

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