LEED AND EELS STUDIES ON VANADIUM (110) AND (111) SINGLE-CRYSTAL SURFACES

The surface atomic arrangements and the electronic states of vanadium (110) and (111) single crystals have been investigated at room temperature with low energy electron diffraction (LEED) and electron spectroscopic techniques. LEED was observed with a CCD camera. The LEED pattern of the most densely packed (I 10) plane showed no extra features beyond those expected for the bulk, while the (111) surface was observed to reconstruct into a (square-root 3 x square-root 3)R30-degrees superstructure. Electron energy loss spectra for both specimens were also measured with primary electrons in the low energy range from 100 to 300 eV. The loss peaks observed for the (110) and (111) surfaces could be attributed to such common energy losses as bulk and surface plasmons, interband transitions and inner-shell excitations. However, the magnitudes of the observed plasmon loss energy with low energy incidence for the (111) surface differ from values calculated on the basis of Ritchie's formula [Phys. Rev. 106 (1957) 874].