Investigation of the stability and charge states of vacancy in clusters Si$_{29}$ and Si$_{38}$

TL;DR

This study investigates the stability and charge distribution of vacancies in silicon clusters Si$_{29}$ and Si$_{38}$ using theoretical methods, revealing stability only in hydrogenated clusters and detailing the resulting structural and electronic changes.

Contribution

It provides new insights into vacancy stability and charge states in silicon clusters, especially highlighting the effects of hydrogenation and symmetry transition.

Findings

Vacancies are unstable in pure dimerized clusters.

Hydrogenated clusters have stable vacancies with symmetry transition.

All silicon atoms become negatively charged near vacancies.

Abstract

Stability and charge states of vacancy in Si$_{29}$ and Si$_{38}$ clusters have been calculated by non-conventional tight-binding method and molecular dynamics. Based on the theoretical calculations, it was shown that the vacancy in pure dimerized clusters is unstable, while in hydrogenated Si$_{29}$H$_{24}$ and Si$_{38}$H$_{30}$ clusters it is stable, but leads to a distortion of its central part with the transition of symmetry from Td to $C_{3v}$ and a change in the forbidden gap. The charges of cluster atoms in the presence of a vacancy are distributed so that all silicon atoms acquire a stable negative charge, which occurs due to the outflow of electrons of the central atom to the neighboring spheres.