Magnetism in defected single-walled boron nitride nanotubesR. Moradian1, 2, 3 and S. Azadi1, 2
1 Physics Department, Faculty of Science, Razi University - Kermanshah, Iran
2 Nano Science and Nano Technology Research Center, Razi University - Kermanshah, Iran
3 Computational Physical Science Research Laboratory, Department of Nano-Science, Institute for Studies in Theoretical Physics and Mathematics (IPM) - P.O. Box 19395-5531, Tehran, Iran
received 11 March 2008; accepted in final form 16 May 2008; published July 2008
published online 13 June 2008
We have investigated the electronic properties of defected boron nitride nanotubes (BNNTs) for spin-up and spin-down electrons by using the first-principle density functional theory. Two types of defects have been considered, vacancy and substitution of carbon and oxygen by boron or nitrogen. The formation energy calculation shows that for both vacancies defected zigzag and armchair BNNTs, the probability of the nitrogen vacancy case is higher than that of the boron vacancy. Also in the carbon doping process of BNNTs, the substitution of boron by carbon is more possible with respect to nitrogen by carbon. In the oxygen doping substitution process, substitution of boron by oxygen is less favorable than nitrogen by oxygen. For the higher-probability cases the spin-up and spin-down band structures show different features. For the first and second cases, the spin-up band structure shows a n-type semiconductor, while the spin-down band structure illustrates a wide band gap semiconductor. But for the oxygen-doped BNNTs case, the spin-up band structure shows a wide band gap semiconductor, while the spin-down band structure illustrates a n-type semiconductor. All defected BNNTs have a 1.0B total magnetic moment.
71.15.Mb - Density functional theory, local density approximation, gradient and other corrections.
31.15.es - Applications of density-functional theory (e.g., to electronic structure and stability; defect formation; dielectric properties, susceptibilities; viscoelastic coefficients; Rydberg transition frequencies).
61.46.Fg - Nanotubes.
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