experimental study of LEED and UPS on bombarded and vacuum cleaved zinc(0001) surfaces

Several Zn single crystals were grown by the Bridgman method and their orientations were determined by the Laue X-ray back-reflection method. Zn(0001) surfaces were prepared by vacuum cleaving and by Ar+ bombardment with annealing. LEED patterns and UPS spectra were taken on both the cleaved and bombarded Zn(0001) surfaces. The LEED patterns from cleaved surfaces showed 6-fold symmetry whereas those from bombarded surfaces showed a hexagonal array but with some differences: the spots with the same distances from the center of LEED pattern had different intensities and they were dimmer and more blurry compared to those from the cleaved surface. A value of 2.64+-0.07 A for the nearest neighbor spacing was determined from the LEED patterns. The UPS spectra showed that for both types of surfaces the 3d peak is at 9.8 eV with a spin splitting of 0.7 eV, which are in agreement with previous experimental and theoretical results. Differences in spectra between the two types of surfaces were found in the ratios of signal/background and in the ratios of the 3d doublet.