Electronic structure of vacancy and chemisorptive bond on Si(111) surface by the DV-Xα cluster calculation

Abstract

The electronic structure of the Si(111) surface is investigated by the first-principle Dv (discrete-variational)-Xα method with the use of several model clusters such as Si13,12, H15, Si16H21, and Si19H21. Chemisorptions of H, Cl, and Ag on the Si(111) surface are also studied. Those characteristics in the electronic structure which are closely related with surface atomic arrangements and chemisorption geometries are clarified in detail. The present calculation shows that surface vacancy is essential in order to give an electronic structure which corresponds well with the observed UPS on the Si(111) 7 × 7 surface. Furthermore, for the Si(111)/Ag system it is elucidated that the Ag atom is chemisorbed on top of the Si atom at the low temperature phase.