2004/07/31 by Dmitry S. Novikov · 3 citations
Chemistry · Materials Science · Physics and Astronomy · #Carbon Nanotubes in Composites #Fullerene Chemistry and Applications #Graphene research and applications #cond-mat.mes-hall #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.72.235428
published as Phys. Rev. B 72, 235428 (2005) · 21 pgs, 8 figs
openalex publication_date 2005/12/30 · arxiv created 2006/01/03 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
A periodic potential applied to a nanotube is shown to lock electrons into incompressible states that can form a devil's staircase. Electron interactions result in spectral gaps when the electron density (relative to a half-filled carbon \ensuremathπ band) is a rational number per potential period, in contrast to the single-particle case where only the integer-density gaps are allowed. When electrons are weakly bound to the potential, incompressible states arise due to Bragg diffraction in the Luttinger liquid. Charge gaps are enhanced due to quantum fluctuations, whereas neutral excitations are governed by an effective SU(4)\ensuremath≃O(6) Gross-Neveu Lagrangian. In the opposite limit of the tightly bound electrons, effects of exchange are unimportant, and the system behaves as a single fermion mode that represents a Wigner crystal pinned by the external potential, with the gaps dominated by the Coulomb repulsion. The phase diagram is drawn using the effective spinless Dirac Hamiltonian derived in this limit. Incompressible states can be detected in the adiabatic transport setup realized by a slowly moving potential wave, with electron interactions providing the possibility of pumping of a fraction of an electron per cycle (equivalently, in pumping at a fraction of the base frequency).