Surface reconstruction of Y(112̄0)

Abstract

The authors report the first observation of surface reconstruction in a HCP metal. Above about 610 K low-energy electron diffraction (LEED) patterns from the (112(mean)0) face of yttrium metal have twofold symmetry and are characteristic of the ideal surface. Below this temperature the patterns comprise two principal and congruent sets of diffraction spots, each with sixfold symmetry, rotated by 30 degrees with respect to each other. They suggest that the transition, which is accompanied by substantial changes in UV photoemission spectra, corresponds to the formation of terraces of close-packed atoms on the surface, involving a approximately 60% increase in atom density.