Dynamic buckling of Si tetramers on the Si(111)-7x7

TL;DR

This study uses first principles calculations to show that Si tetramers on the Si(111)-7x7 surface are dynamically buckling, affecting STM imaging and providing new insights into their atomic structure during homoepitaxy.

Contribution

It reveals the instability of Si tetramers against buckling and links dynamic buckling to STM image features, advancing understanding of surface atomic structures.

Findings

Si tetramers are dynamically buckled on Si(111)-7x7 surface

Buckling influences STM image interpretation

First principles calculations match experimental STM data

Abstract

The atomic structure of Si tetramers that form on the Si$(111)\textrm{-}7\times7$ surface during homoepitaxy, is investigated by means of first principles calculations with the currently available atomistic model as starting point. It is demonstrated that the rectangular shape of the Si tetramer is unstable against buckling. Comparison of calculated results with available scanning tunnelling microscopy (STM) data provides a new understanding of the problem, indicating that the recorded STM images are influenced by dynamic buckling.