First-Principles Studies of Hydrogenated Si(111)--7$\times$7

TL;DR

This study uses first-principles molecular dynamics to analyze hydrogenated Si(111)-7×7 surfaces, identifying energetically favorable phases and matching experimental STM data.

Contribution

It provides detailed first-principles insights into the geometries and electronic properties of hydrogenated Si(111)-7×7 surfaces, including energetically preferred hydrogen configurations.

Findings

Monohydride phase is energetically favorable.

Nearly equivalent energy for fully saturated hydrogen phase.

Calculated features agree with experimental STM data.

Abstract

The relaxed geometries and electronic properties of the hydrogenated phases of the Si(111)-7$\times$7 surface are studied using first-principles molecular dynamics. A monohydride phase, with one H per dangling bond adsorbed on the bare surface is found to be energetically favorable. Another phase where 43 hydrogens saturate the dangling bonds created by the removal of the adatoms from the clean surface is found to be nearly equivalent energetically. Experimental STM and differential reflectance characteristics of the hydrogenated surfaces agree well with the calculated features.