Orientational epitaxy of the hexagonally reconstructed Pt(001) surface

Abstract
We describe x-ray-scattering studies of the orientational epitaxy displayed by the hexagonally reconstructed Pt(001) surface. At 1685 K, the reconstructed surface layer undergoes a continuous rotational transformation with respect to the underlying bulk and exhibits mean-field behavior. A second, discontinuous rotational transformation is observed at 1580 K. These results are inconsistent with the predictions of current theories and lead us to propose a mean-field description of rotational transformations.