title: Spin configurations of a carbon nanotube in a nonuniform external potential
abstract: We study, theoretically, the ground state spin of a carbon nanotube in the presence of an external potential. We find that when the external potential is applied to a part of the nanotube, its variation changes the single electron spectrum significantly. This, in combination with Coulomb repulsion and the symmetry properties of a finite length armchair nanotube, induces spin flips in the ground state when the external potential is varied. We discuss the possible application of our theory to recent measurements of Coulomb-blocked peaks and their dependence on a weak magnetic field in armchair carbon nanotubes.
authors.affiliation: Lyman Laboratory of Physics, Harvard University, Cambridge, Massachusetts 02138, USA.
authors.initials: Y
authors.lastname: Oreg
authors.initials: K
authors.lastname: Byczuk
authors.initials: BI
authors.lastname: Halperin