INTERPRETATION OF THE PHOTOEMISSION SPECTRA OF PB SI(111)-(7X7) IN THE INITIAL-STAGES OF THE PB CHEMISORPTION - A THEORETICAL-STUDY/

In a recent theoretical study of the adsorption and diffusion mechanis ms of Pb on the Si(111)-(7 x 7) surface in the initial stages of the D b chemisorption, two adsorption mechanisms were especially considered: (i) adsorption of Db atoms on Si dangling bonds; (ii) Db adsorption w ith formation of Db clusters. The second mechanism was found to be mor e favorable than the first one, but the two mechanisms may coexist. Th e tendency to agglomeration was explained by strong interaction betwee n the Pb atoms. In this paper, we focus on an interpretation of the ph otoemission spectra observed for the Pb/Si(111)-(7 x 7) system. Densit ies of states performed on models based on these two mechanisms allow us to propose an interpretation for the two surface states experimenta lly observed in the projected band structure of Pb/Si(111)-(7 x 7). (C ) 1998 Elsevier Science B.V. All rights reserved.