# An optimized interatomic potential for silicon and its application to thermal stability of silicene

## TL;DR

This paper develops a new optimized interatomic potential for silicon that accurately models various properties and predicts that bilayer silicene is thermally stable at room temperature, unlike single-layer silicene.

## Contribution

A novel optimized interatomic potential for silicon is introduced, improving accuracy over existing models and enabling better predictions of silicene's thermal stability.

## Key findings

- The new potential accurately reproduces silicon properties.
- Single-layer silicene is unstable at room temperature.
- Bilayer silicene remains stable at ambient conditions.

## Abstract

An optimized interatomic potential has been constructed for silicon using a modified Tersoff model. The potential reproduces a wide range of properties of Si and improves over existing potentials with respect to point defect structures and energies, surface energies and reconstructions, thermal expansion, melting temperature and other properties. The proposed potential is compared with three other potentials from the literature. The potentials demonstrate reasonable agreement with first-principles binding energies of small Si clusters as well as single-layer and bilayer silicenes. The four potentials are used to evaluate the thermal stability of free-standing silicenes in the form of nano-ribbons, nano-flakes and nano-tubes. While single-layer silicene is mechanically stable at zero Kelvin, it is predicted to become unstable and collapse at room temperature. By contrast, the bilayer silicene demonstrates a larger bending rigidity and remains stable at and even above room temperature. The results suggest that bilayer silicene might exist in a free-standing form at ambient conditions.