Transports of Disordered Carbon Nanotubes with Long Range Coulomb Interaction

Transport properties of disordered carbon nanotubes are investigated with including long range Coulomb interactions. The resistivity and optical conductivity are calculated by using the memory functional method. In addition, the effect of localization is taken into account by use of the renormalization group analysis and it is shown that the backward scattering of the intra-valley and that of the inter-valley cannot coexist in the localized regime.Comment: 4 pages, 2 figures, epsf.sty, submitted to Phys. Rev.

Tomonaga-Luttinger-Liquid Theory of Metallic Carbon Nanotubes with Open Boundaries

Tomonaga-Luttinger-liquid theory is formulated for metallic carbon nanotubes with open boundaries. Both cases of single- and multi-wall nanotubes are discussed. Based on this theory, spatial variation of the charge density from an edge is investigated with taking account of the shift of the chemical potential which expresses the carrier injection to the nanotube. The charge density has the spatially independent part and the oscillatory component. Roles of Coulomb interaction on the amplitude of the oscillation, the wavenumbers of it and the uniform component of the charge density are clarified.Comment: 14 pages, 4 figures, to be published in J. Phys. Soc. Jpn. Vol. 71 (2002) No.1

Charge-Ordered State versus Dimer-Mott Insulator at Finite Temperatures

We theoretically investigate the competition between charge-ordered state and Mott insulating state at finite temperatures in quarter-filled quasi-one-dimensional electron systems, by studying dimerized extended Hubbard chains with interchain Coulomb interactions. In order to take into account one-dimensional fluctuations properly, we apply the bosonization method to an effective model obtained by the interchain mean-field approximation. The results show that lattice dimerization, especially in the critical region, and frustration in the interchain Coulomb interactions reduce the charge-ordering phase transition temperature and enlarge the dimer-Mott insulating phase. We also derive a general formula of the Knight shift in the charge-ordered phase and its implication to experiments is discussed.Comment: 5 pages, 4 figures, to be published in J. Phys. Soc. Jpn. Vol.76 No.1

Crossover between High and Low Energy-States in Two-Coupled Chains of Tomonaga Model

By applying the renormalization group method to two-coupled chains in the Tomonaga model, the role of interchain hopping has been studied in the entire energy region. The energy for a crossover from the perturbational regime to the relevant regime becomes smaller than that of the interchain hopping due to one-dimensional fluctuations of the mutual interaction. From the calculation of response functions for charge density waves and superconducting states, the phase diagram of dominant and subdominant states has been obtained in the plane of mutual interactions with fixed energy.Comment: 18 pages, 9 figures, to be published in Prog. Theor. Phys. 98 (1997) No.

Amount and availability of forest biomass as an energy resource in a mountainous region in Japan: a GIS-based analysis

Feasibility of energy utilization of forest biomass in a mountainous region in Japan has been discussed with the aid of a geographic information system (GIS). In this study, logging residues, thinned trees, and broad-leaved forests are defined as forest biomass. First, the distribution map of biomass resources has been completed by use of the GIS, and information on topography of each sub-compartment has been prepared. Second, harvesting and transporting systems have been classified into six types according to the parts of tree used as energy source (two types) and topographical conditions (three types). The equations for calculating the costs whose variables are slope, skidding/yarding distance, and transporting distance have been developed. Finally, the relationship has been analyzed between the mass and procurement cost of forest biomass in the region. As a result, logging residues [the annual available amount is 4,035 t/y1 (DM2)] proved to be the most cost effective, followed by broad-leaved forests [0,317 t/y (DM)]; thinned trees [27,854 t/y (DM)] proved to be the most costly. This analysis could be of help in drawing an operational plan, i.e., in selecting sub-compartments to be felled. For instance, it has been calculated that the amount of biomass resources of 30,106 t/y (DM) was required for the construction of a power-generation plant that covered 24.8%of the power consumed by households in the region. To obtain this amount of forest biomass for energy purposes, forest biomass should be harvested in sub-compartments, whose procurement costs are lower than 13,037 yen/t (DM)

Geometry-Driven Shift in the Tomonaga-Luttinger Exponent of Deformed Cylinders

We demonstrate the effects of geometric perturbation on the Tomonaga-Luttinger liquid (TLL) states in a long, thin, hollow cylinder whose radius varies periodically. The variation in the surface curvature inherent to the system gives rise to a significant increase in the power-law exponent of the single-particle density of states. The increase in the TLL exponent is caused by a curvature-induced potential that attracts low-energy electrons to region that has large curvature.Comment: 4 pages, 5 figure