Angle-resolved photoelectron-spectroscopy study of the Si(111)3×3-Sn surface: Comparison with Si(111)3×3-Al, -Ga, and -In surfaces

Abstract

Angle-resolved ultraviolet photoelectron spectra have been measured for the Si(111) $\sqrt{3}\times \sqrt{3}$-Sn surface. It has been found that the surface-state dispersions are very similar to those reported for the Si(111) $\sqrt{3}\times \sqrt{3}$-Al, -Ga, and -In (column-III metals) surfaces except for the presence of an additional metallic surface state. The metallic state observed for the $\sqrt{3}\times \sqrt{3}$-Sn surface seems to correspond to the otherwise unoccupied surface state for the $\sqrt{3}\times \sqrt{3}-M$ ($M=\mathrm{Al}, \mathrm{Ga}, \mathrm{In}$) surfaces. This suggests that the surface atomic geometry of the $\sqrt{3}\times \sqrt{3}$-Sn is essentially the same as those of the $\sqrt{3}\times \sqrt{3}-M$ surfaces, in which a metal atom is situated in every $\sqrt{3}\times \sqrt{3}$ threefold-hollow site.