Role of vacancies in the magnetic and electronic properties of SiC nanoribbons: an ab initio study

TL;DR

This study uses ab-initio density functional theory calculations to explore how vacancies affect the electronic and magnetic properties of zigzag SiC nanoribbons, revealing vacancy-induced magnetism and potential for ferromagnetic applications.

Contribution

It provides new insights into vacancy effects on SiC nanoribbons' properties and how impurity interactions can modify their magnetic and electronic behavior.

Findings

Single vacancies induce magnetism in Z-SiCNRs.

V_C causes a transition from half-metallic to metallic behavior.

Impurities can suppress magnetism and preserve half-metallicity.

Abstract

Using ab-initio calculations based on density functional theory, we investigate the effects of vacancies on the electronic and magnetic properties of zigzag SiC nanoribbons (Z-SiCNR). Single (V_C and V_Si) and double (V_SiV_Si and V_SiV_C) vacancies are observed to induce magnetism in Z-SiCNRs. The presence of a single V_Si does not affect the half-metallic behavior of pristine Z-SiCNRs; however, a single V_C leads to a transition from half-metallic to metallic behavior in Z-SiCNRs due to the edge Si p orbitals and the atoms surrounding the vacancy. The interactions of vacancies with foreign impurity atoms (B and N) are also investigated and it is observed that V_SiN_C does not only suppress the oscillatory type magnetism of V_SiV_C, but also retains the half-metallic character of the pristine Z-SiCNRs. The defect formation energies of vacancies can be reduced by substitutional B and N atoms. We believe that ferromagnetism is expected if Z-SiCNR are grown under suitable conditions.