Stability and structure of atomic chains on Si(111)

TL;DR

This study investigates the stability and structure of atomic chains on Si(111) surfaces induced by various adsorbates, revealing that pure silicon chain structures are thermodynamically stable and that electron counting explains their stability.

Contribution

The paper introduces a simple electron-counting rule to understand the stability and structure of atomic chains on Si(111), supported by first-principles calculations and microscopy.

Findings

Only silicon honeycomb or Seiwatz chains are thermodynamically stable.

Mixed chain configurations can be kinetically stable.

Electron counting explains chain stability and structure.

Abstract

We study the stability and structure of self-assembled atomic chains on Si(111) induced by monovalent, divalent and trivalent adsorbates, using first-principles total-energy calculations and scanning tunneling microscopy. We find that only structures containing exclusively silicon honeycomb or silicon Seiwatz chains are thermodynamically stable, while mixed configurations, with both honeycomb and Seiwatz chains, may be kinetically stable. The stability and structure of these atomic chains can be understood using a surprisingly simple electron-counting rule.