Atomic structure and electronic properties of the In/Si(111)2×2 surface

Abstract

The Si(111)2$\ifmmode\times\else\texttimes\fi{}$2-In reconstruction can be considered as a precursor phase for the formation of the metallic $\sqrt{7}\ifmmode\times\else\texttimes\fi{}\sqrt{3}$ phases of In overlayers on a Si(111) surface. Using the ab initio random structure searching method, comparison of simulated and experimental scanning tunneling microscopy images, and resemblance of the calculated band structure to the experimental angle-resolved photoelectron spectra, we examined various 2$\phantom{\rule{0.16em}{0ex}}\ifmmode\times\else\texttimes\fi{}\phantom{\rule{0.16em}{0ex}}$2 structure models with 0.5, 0.75, 1.0, and 1.25 monolayer In coverage. The only model which fits well all the requirements is the one-monolayer model, where three In atoms in the ${T}_{4}$ sites form a trimer centered in the ${H}_{3}$ site and the fourth In atom occupies the on-top (${T}_{1}$) site.