Spin splitting at the Fermi level in carbon nanotubes in the absence of a magnetic field Márcio M. Cunha, Júlio Brandão, Jonas R.F. Lima and Fernando Moraes Eur. Phys. J. B, 88 11 (2015) 288 Published online: 03 November 2015 DOI: 10.1140/epjb/e2015-60572-8