Tamm states of carbon nanotubes

Abstract
The fine structure of the π-electron spectrum of semi-infinite carbotubulenes (cylindrical graphene tubes) is investigated. Together with closed short-diameter tubelenes, open nanotubes whose terminal fragments contain heteroatoms are studied. Algebraic equations are obtained for the one-electron energy levels corresponding to wave functions localized on a terminal fragment. It is shown that Tamm energy levels, lying in either the band gaps or the continuous spectrum (resonance states), can exist in the systems studied.