Theoretical study of magnetic moments induced by defects at the SiC(110) surface

Abstract

The effect of different surface defects on the atomic and electronic structures of cubic β-SiC(110) surface are studied by means of a first-principles calculation based on density-functional theory using the siesta code. In the calculations, different spin populations at each atom are allowed. We find that while adsorption of atomic O, N, or H on surface C atoms do not induce magnetic moments on SiC(110), Si vacancies, substitutional C at the Si sites, and H or F adsorbed on Si surface sites induce localized magnetic moments as large as 0.7 μB at the C atoms close to the defect. The local magnetic moment arrangement varies from ferromagnetic in the case of H adsorption to antiferromagnetic in the Si vacancy and substitutional C cases. The case of H adsorption on Si surface atoms is discussed in detail. It is concluded that magnetism is mainly owing to the local character of the C valence orbitals. © 2011 American Physical Society.