A study of Mg adsorption on Si(001) surface from first principles

TL;DR

This study uses first-principles density functional theory calculations to investigate how magnesium atoms adsorb onto the silicon (001) surface at various coverages, identifying preferred sites and surface reconstructions.

Contribution

It provides detailed first-principles insights into Mg adsorption sites and surface reconstructions on Si(001), which were previously not fully understood.

Findings

Most favorable Mg adsorption site at 1/4 and 1/2 ML is the cave site.

At 1 ML coverage, Mg prefers shallow sites on 2x1 reconstructed surface.

Minimum energy configurations vary with coverage, showing different surface reconstructions.

Abstract

First-principles calculations using density functional theory based on norm-conserving pseudopotentials have been performed to investigate the Mg adsorption on the Si(001) surface for 1/4, 1/2 and 1 monolayer coverages. For both 1/4 and 1/2 ML coverages it has been found that the most favorable site for the Mg adsorption is the cave site between two dimer rows consistent with the recent experiments. For the 1 ML coverage we have found that the most preferable configuration is when both Mg atoms on 2x1 reconstruction occupy the two shallow sites. We have found that the minimum energy configurations for 1/4 ML coverage is a 2x2 reconstruction while for the 1/2 and 1 ML coverages they are 2x1.