title: Degeneracy in carbon nanotubes under transverse magnetic δ-fields.
abstract: The aim of this article was to study the degeneracy of the energy spectrum in a nanotube under a transverse magnetic field. The massless Dirac-Weyl equation has been used to describe the low energy states of this system. The particular case of a singular magnetic field approximated by Dirac delta distributions is considered. It is shown that, under general symmetry conditions, there is a double degeneracy corresponding to periodic solutions with null axial momentum k(z)=0. Also, there may be a kind of sporadic degeneracy for non-vanishing values of k(z), which are explicitly computed in the present example. The proof of these properties is obtained by means of the supersymmetric structure of the Dirac-Weyl Hamiltonian.
authors.affiliation: Department of Physics, Faculty of Science, Ankara University, 06100 Ankara, Turkey.
authors.forename: Ş
authors.initials: Ş
authors.lastname: Kuru
authors.forename: J
authors.initials: J
authors.lastname: Negro
authors.forename: S
authors.initials: S
authors.lastname: Tristao