Magnetoelectronic properties of nanographite ribbons

Magnetoelectronic structures of the AA- and AB-stacked nanographite ribbons, which strongly depend on magnitude and direction of magnetic field, ribbon edges, and interribbon interactions, are studied within the frame of tight-binding model. First, the origins of Landau subbands and additional spectra, induced by the perpendicular magnetic field B-perpendicular to, chiefly changing the intraribbon interaction, are analytically studied in the zigzag systems. This method allows us to intuitively understand the magnetoband structures of the finite size systems. Then, the interribbon interactions modify Landau subbands and change energy dispersions, energy spacing, bandwidth and oscillation period of Landau subbands. On the other hand, the parallel magnetic field B-parallel to changes the interribbon interactions and leads to the Landau levels along k(z). Furthermore, B-parallel to can induce the metal-insulator transition in the AB-stacked armchair ribbons. Above all, magnetic field and interribbon interactions vitalize the magnetoband structures. So, there are rich structures in density of states: sharp peaks, square-root peaks, logarithmic divergences and oscillating structures. Finally, DOS can clearly exhibit OD, I D and 2D characteristics. And this specific is expected to have great effects on the physical properties, e.g. optical, magnetic and transport properties, of the stacked ribbons. (c) 2004 Elsevier B.V. All rights reserved.