# Pentagons in the Si$(331)-(12\times1)$ surface reconstruction

## TL;DR

This study combines microscopy and ab initio calculations to propose a structural model of the Si(331)-(12×1) surface, highlighting the role of pentagons in reducing surface energy and predicting multiple buckled configurations.

## Contribution

The paper introduces a novel structural model of the Si(331) surface featuring pentagons, advancing understanding of high-index silicon surface reconstructions.

## Key findings

- Pentagons lower the surface energy of Si(331)
- Multiple buckled configurations with similar energies are predicted
- Structural model aligns with experimental microscopy data

## Abstract

The microscopic structure of the high-index Si$(331)-(12\times1)$ surface is investigated combining scanning tunneling microscopy with ab initio calculations. We present a structural model of the Si(331) surface, employing a reconstruction element composed of six pentagons integrated to the structure of the adjacent pentamer with an interstitial atom. We demonstrate that appropriately arranged additional pentagons significantly lower the surface energy of the high-index surface. The model predicts the existence of multiple Si(331) buckled configurations with similar energies.