141 research outputs found
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
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