NEW SURFACE PHASES FOR POTASSIUM ADATOMS ON CLEAVED SI(111)

In a previous study (B. Reihl and K.O. Magnusson, Phys. Rev. B 42 (199 0) 11839) no change was observed in the LEED pattern from the 2x1 patt ern of the clean Si(lll) surface upon potassium adsorption, In contras t to this paper, we observe six surface phases during room temperature dosing of K on the cleaved Si(lll) surface. In addition, Ne observe a 3x1 pattern on the cleaved K/Si(111) surface upon annealing. This pap er will provide photographs of the new phases observed with LEED. It a lso will set limits on the K coverage required far these phases using results from photoemission and secondary electron cutoff measurements. Tentative models for these surfaces will be proposed. These new LEED results show a more complex interaction between K and the cleaved Si(1 11) surface than previously thought and hopefully will encourage furth er exploration of adsorption on the cleaved Si(lll) surface. (C) 1997 Elsevier Science B.V.