Structure Stability and Electronic Property for Alkaline-Earth Metals Induced Si(111)-3x2 Surfaces

TL;DR

This study uses ab initio calculations to analyze the stability and electronic properties of alkaline-earth metal-induced Si(111)-3x2 surfaces, revealing stable structures and surface band gaps consistent with experiments.

Contribution

It provides a comprehensive theoretical analysis of Ca, Sr, and Ba induced Si(111)-3x2 surfaces, elucidating their stability and electronic characteristics.

Findings

High structural stability due to strong chemical bonds.

Surface band gap of 1.65-1.68 eV consistent with experiments.

Electronic states derived from top Si and metal atoms.

Abstract

Structural stability and electronic properties of alkaline-earth metals (Ca, Sr, Ba) induced Si(111)-3x2 surfaces have been comprehensively studied by means of ab initio calculations. Adsorption energy and charge density difference calculations show the high structural stability due to the strong chemical bonding. Analysis of electronic band structures and band-decomposed charge density distributions indicates that the third valence band is deriving from top Si and metal atoms, while the top most two valence bands are deriving from the bulk silicon. These results suggest a larger surface band gap of 1.65-1.68 eV, which is good consistent with the recent experimental finding for Sr/Si(111)-3x2 surface. These results reveal a natural explanation for the relevant experimental observation and stimulate further experimental and theoretical exploration on the surface science.