1207.6342 (Juliana M. Morbec et al.)

Magnetic and electronic properties of SiC nanoribbons: role of defects    [PDF]

Juliana M. Morbec, Gul Rahman

Using {\it 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 ($V_{\rm C}$ and $V_{\rm Si}$) and double ($V_{\rm Si}V_{\rm Si}$ and $V_{\rm Si}V_{\rm C}$) vacancies are observed to induce magnetism in Z-SiCNRs. The presence of a single $V_{\rm Si}$ does not affect the half-metallic behavior of pristine Z-SiCNRs; however, a single $V_{\rm C}$ leads to a transition from half-metallic to metallic behavior in Z-SiCNRs due to the edge Si $p$ orbitals. The interactions of vacancies with foreign impurity atoms (B and N) were also investigated and it is observed that $V_{\rm Si}N_{\rm C}$ does not only suppress the oscillatory type magnetism of $V_{\rm Si}V_{\rm C}$, 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.

View original: http://arxiv.org/abs/1207.6342