Ferromagnetism Induced by Intrinsic Defects and Boron Substitution in Single-Wall SiC Nanotubes

Abstract

On the basis of density functional theory (DFT) methods, we study the magnetic properties and electronic structures of the armchair (4, 4) and zigzag (8, 0) single-wall SiC nanotubes with various vacancies and boron substitution. The calculation results indicate that a Si vacancy could induce the magnetic moments in both armchair (4, 4) and zigzag (8, 0) single-wall SiC nanotubes, which mainly arise from the p orbital of C atoms surrounding Si vacancy, leading to the ferromagnetic coupling. However, a C vacancy could only bring about the magnetic moment in armchair (4, 4) single-wall SiC nanotube, which mainly originates from the polarization of Si p electrons, leading to the antiferromagnetic coupling. In addition, for both kinds of single-wall SiC nanotubes, magnetic moments can be induced by a boron atom substituting for C atom. When two boron atoms locate nearest neighbored, both kinds of single-wall Si(C, B) nanotubes exhibit antiferromagnetic coupling.