A First-Principles Study of Defects and Adatoms in Silicon Carbide Honeycomb Structures

TL;DR

This study uses first-principles calculations to explore the stability, electronic, magnetic, and defect-related properties of 2D silicon carbide honeycomb structures and nanoribbons, revealing potential for functionalization.

Contribution

It provides a comprehensive first-principles analysis of defects, adatoms, and impurities in 2D SiC honeycomb structures, highlighting their effects on physical properties and magnetic behavior.

Findings

2D SiC monolayer is stable and non-magnetic with a wide band gap.

Vacancies and impurities can induce magnetic moments and alter electronic properties.

Mechanical properties and dimensionality effects are systematically characterized.

Abstract

We present a study of mechanical, electronic and magnetic properties of two dimensional (2D), monolayer of silicon carbide (SiC) in honeycomb structure and its quasi 1D armchair nanoribbons using first-principles plane wave method. In order to reveal dimensionality effects, a brief study of 3D bulk and 1D atomic chain of SiC are also included. Calculated bond-lengths, cohesive energies, charge transfers and band gaps display a clear dimensionality effect. The stability analysis based on the calculation of phonon frequencies indicates that 2D SiC monolayer is stable in planar geometry. We found that 2D SiC monolayer in honeycomb structure and its bare and hydrogen passivated nanoribbons are ionic, non-magnetic, wide band gap semiconductors. The band gap is further increased upon self-energy corrections. The mechanical properties are investigated using the strain energy calculations. The effect of various vacancy defects, adatoms and substitutional impurities on electronic and magnetic properties in 2D SiC monolayer and in its armchair nanoribbons are also investigated. Some of these vacancy defects and impurities, which are found to influence physical properties and attain magnetic moments, can be used to functionalize SiC honeycomb structures.