Auger fine structures of surface states for Si(111)7×7 and Si(111)√3 × √3-Al

Abstract

Auger fine structures of SiLVV and AlLVV spectra are observed for Si(111)7 × 7 and Si(111)3 × 3-Al in the second derivative mode and regarded as transitions from surface states to 2p levels. For Si(111)7 × 7, three satellite peaks are observed close to the bulk peak of SiLVV, whereas for Si(111)3 × 3 -Al, two and one satellite peaks are observed in the AlLVV and SiLVV spectra, respectively. The origin of these satellite peaks is analyzed referring to the surface states which were observed in photoemission spectroscopy. The Auger energies of these satellite peaks consist with the surface state energies measured in photoemission and scanning tunneling spectroscopy (STS). As a result, it is found that possible Auger transitions from surface states to 2p levels are localized in the individual surface atoms to which the initial and final states belong and explained reasonably by assuming DAS and modified T4 structure models for Si(111)7 × 7 and Si(111)3 × 3 -Al, respectively.