Energetics and stability of dangling-bond silicon wires on H passivated Si(100)

TL;DR

This study uses density functional theory to analyze the electronic, geometric, and energetic properties of dangling-bond silicon wires on H-passivated Si(100), revealing their potential for molecular devices due to localized states and stability features.

Contribution

It provides new insights into the stability, electronic states, and magnetic ordering of finite dangling-bond silicon wires, highlighting their suitability for future nanoelectronic applications.

Findings

Finite wires develop localized electronic states useful for devices.

Infinite wires are insulating and undergo Peierls distortion.

Energy barriers for diffusion are around 1 eV or higher.

Abstract

We evaluate the electronic, geometric and energetic properties of quasi 1-D wires formed by dangling bonds on Si(100)-H (2 x 1). The calculations are performed with density functional theory (DFT). Infinite wires are found to be insulating and Peierls distorted, however finite wires develop localized electronic states that can be of great use for molecular-based devices. The ground state solution of finite wires does not correspond to a geometrical distortion but rather to an antiferromagnetic ordering. For the stability of wires, the presence of abundant H atoms in nearby Si atoms can be a problem. We have evaluated the energy barriers for intradimer and intrarow diffusion finding all of them about 1 eV or larger, even in the case where a H impurity is already sitting on the wire. These results are encouraging for using dangling-bond wires in future devices.