Competition between
Surface Roughening and Reconstruction
in (110) Facets of FCC Crystals

Marcel den Nijs

Department of Physics, University of Washington,
Seattle, Washington 98195-1560

Physical Review B 46, 10386 (1992)


Surface roughening induces a simultaneous deconstruction transition in missing row reconstructed (110) facets of FCC crystals. This transition can be described by the 4-state chiral clock-step model. Numerical finite size scaling results indicate that at zero chirality this transition has the character of a super imposed Kosterlitz-Thouless type roughening and Ising type deconstruction transition. A symmetry property of the model, called S-T invariance, and related to super symmetry, elucidates this aspect. In the strong chirality limit a fermion analysis applies. The full phase diagram can be constructed by combining these numerical and analytical results. Pt(110) and Au(110) follow specific paths through it. The only path consistent with the current experimental evidence for Pt(110) is a roughening induced simultaneous deconstruction transition, which has the character of an incommensurate melting transition with respect to the reconstruction degrees of freedom. This implies that the difference in energy between clockwise and anti-clockwise steps is small in Pt(110).

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