Magnetism induced by single carbon vacancies in a three-dimensional graphitic network

We present an ab initio density functional theory study of the magnetic moments that arise in graphite by creating single carbon vacancies in a three-dimensional (3D) graphite network using full potential, all electron, spin polarized electronic structure calculations. In previous reports, the appearance of magnetic moments was explained in a two-dimensional graphene sheet just through the existence of the vacancies itself [Carbon-Based Magnetism, edited by F. Palacio and T. Makarova (Elsevier, Amsterdam, 2005); D. C. Mattis, Phys. Rev. B 71, 144424 (2005); Y. Kobayashi , ibid. 73, 125415 (2006); R. Yoshikawa Oeiras , ibid. (to be published); P. O. Lehtinen , Phys. Rev. Lett. 93, 187202 (2004)]. The dependence of the arising magnetic moment on the nature and geometry of the vacancies for different supercells is reported. We found that the highest value of magnetic moment is obtained for a 3x3x1 supercell and that the highly diluted 5x5x1 supercell shows no magnetic ordering. The results obtained in this paper are indicative of the importance of interlayer interactions present in a 3D stacking. We conclude that this should not be underestimated when vacancy-based studies on magnetism in graphitic systems are carried out.