167 research outputs found
Quantum Hall Effect in Three-dimensional Field-Induced Spin Density Wave Phases with a Tilted Magnetic Field
The quantum Hall effect in the three-dimensional anisotropic tight-binding
electrons is investigated in the field-induced spin density wave phases with a
magnetic field tilted to any direction. The Hall conductivity,
and , are shown to be quantized as a function of the wave vector
of FISDW, while stays zero, where is the most conducting
direction and and are perpendicular to .Comment: 18 pages, REVTeX 3.0, 1 figure is available upon request, to be
published in Physical Review
Two-Coupled Chains with Spin-Anisotropic Backward Scattering
By applying renormalization group method to the bosonized Hamiltonian of
two-coupled chains with repulsive intrachain interaction, we have examined a
role of backward scattering with a spin-anisotropy which competes with
interchain hopping. From calculation of a dominant state in the limit of low
energy, it is found that superconducting state moves into spin density wave
state when the anisotropy becomes larger than a critical value. Further phase
diagram is shown on the plane of g-ology.Comment: 8 pages, 4 figures, to be published in Physica
Response Functions of Two-Coupled Chains of Tomonaga-Luttinger Liquids
Properties of fluctuations in two chains of Tomonaga-Luttinger liquids
coupled by the interchain hopping have been studied by calculating retarded
response functions for charge and \chi^R_{\p}
(q_x,q_y;\omega) for spin where and or ) denote the
longitudinal and transverse wave vector, respectively, and is the
frequency. We have found the notable fact that the repulsive intrachain
interaction results in the clear enhancement of {\rm{Im}}\chi^R_\p
(q_x,\pi;\omega) and the suppression of at low energies. This result indicates the importance of the
dynamical effect by the spin fluctuation with and small ,
which has a possibility to give rise to the attractive interaction for the
electron pairing.Comment: 8 pages, 5 figures, to be published in Physica
Spin-Density-Wave Phase Transitions in Quasi-One-Dimensional Dimerized Quarter-Filled Organic Conductors
We have studied spin density wave (SDW) phase transitions in dimerized
quarter-filled Hubbard chains weakly coupled via interchain one-particle
hopping, . It is shown that there exists a critical value of ,
, between the incoherent metal regime () and the
Fermi liquid regime () in the metallic phase above the SDW
transition temperature. By using the 2-loop perturbative renormalization-group
approach together with the random-phase-approximation, we propose a SDW phase
diagram covering both of the regimes. The SDW phase transition from the
incoherent metal phase for is caused by growth of the
intrachain electron-electron umklapp scattering toward low temperatures, which
is regarded as preformation of the Mott gap. We discuss relevance of the
present result to the SDW phase transitions in the quasi-one-dimensional
dimerized quarter-filled organic conductors, (TMTTF)X and (TMTSF)X.Comment: 19 pages, 13 eps figures, uses jpsj.sty, corrected typo in the text
and figures, no changes to the paper, to appear in J. Phys. Soc. Jpn. 68,
No.8 (1999
Spin-density wave versus superconducting fluctuations for quasi-one-dimensional electrons in two chains of Tomonaga-Luttinger liquids
We study possible states at low temperatures by applying the
renormalization-group method to two chains of Tomonaga-Luttinger liquids with
both repulsive intrachain interactions and interchain hopping. As the energy
decreases below the hopping energy, three distinct regions I, III, and II
appear successively depending on properties of fluctuations. The crossover from
the spin-density wave (SDW) state to superconducting (SC) state takes place in
region III where there are the excitation gaps of transverse charge and spin
fluctuations. The competition between SDW and SC states in region III is
crucial to understanding the phase diagram in the quasi-one-dimensional organic
conductors.Comment: 11 pages, Revtex format, 1 figure, to be published in Phys. Rev.
Spin-density-wave instabilities in the organic conductor (TMTSF)_2ClO_4: Role of anion ordering
We study the spin-density-wave instabilities in the quasi-one-dimensional
conductor (TMTSF)_2ClO_4. The orientational order of the anions ClO_4 doubles
the unit cell and leads to the presence of two electrnic bands at the Fermi
level. From the Ginzburg-Landau expansion of the free energy, we determine the
low-temperature phase diagram as a function of the strength of the Coulomb
potential due to the anions. Upon increasing the anion potential, we first find
a SDW phase corresponding to an interband pairing. This SDW phase is rapidly
supressed, the metallic phase being then stable down to zero temperature. The
SDW instability is restored when the anion potential becomes of the order of
the hopping amplitude. The metal-SDW transition corresponds to an intraband
pairing which leaves half of the Fermi surface metallic. At lower temperature,
a second transition, corresponding to the other intraband pairing, takes place
and opens a gap on the whole Fermi surface. We discuss the consequences of our
results for the experimental phase diagram of (TMTSF)_2ClO_4 at high magnetic
field.Comment: 13 pages, 10 figures, Version 2 with minor correction
Phase Diagram of Superconductivity on the Anisotropic Triangular Lattice Hubbard Model
We study the electronic states of the anisotropic triangular lattice Hubbard
model at half filling, which is a simple effective model for the organic
superconducting -BEDT-TTF compounds. We treat the effect of the Coulomb
interaction by the fluctuation exchange (FLEX) method, and obtain the phase
diagram of this model for various sets of parameters. It is shown that the
d-wave superconductivity is realized in the wide region of the phase diagram,
next to the antiferromagnetic states. The obtained phase diagram explains the
characters of the experimental results very well.Comment: 4 pages, 6 figs, submitted for publicatio
Effects of Spin Fluctuations in Quasi-One-Dimensional Organic Superconductors
We study the electronic states of quasi-one-dimensional organic conductors
using the single band Hubbard model at half-filling. We treat the effects of
the on-site Coulomb interaction by the fluctuation-exchange (FLEX) method, and
calculate the phase diagram and physical properties. The calculated pressure
dependence of the Neel temperature coincides well with the experimental one. We
also show that a pseudogap is formed in the density of states near the chemical
potential and that d-wave superconductivity appears next to the
antiferromagnetic state. Moreover the NMR relaxation rate increases on cooling
in the low-temperature region.Comment: 4 pages, 5 figures, to apprear in J. Phys. Soc. Jp
Orbital quantization in the high magnetic field state of a charge-density-wave system
A superposition of the Pauli and orbital coupling of a high magnetic field to
charge carriers in a charge-density-wave (CDW) system is proposed to give rise
to transitions between subphases with quantized values of the CDW wavevector.
By contrast to the purely orbital field-induced density-wave effects which
require a strongly imperfect nesting of the Fermi surface, the new transitions
can occur even if the Fermi surface is well nested at zero field. We suggest
that such transitions are observed in the organic metal
-(BEDT-TTF)KHg(SCN) under a strongly tilted magnetic field.Comment: 14 pages including 4 figure
The Japan Public Health Center-based Prospective Study for the Next Generation (JPHC-NEXT): Study Design and Participants
Background: Lifestyle and life-environment factors have undergone drastic changes in Japan over the last few decades. Further, many molecular epidemiologic studies have reported that genetic, epigenetic, and other biomarker information may be useful in predicting individual disease risk.Methods: The Japan Public Health Center-based Prospective Study for the Next Generation (JPHC-NEXT) was launched in 2011 to identify risk factors for lifestyle-related disease, elucidate factors that extend healthy life expectancy, and contribute toward personalized healthcare based on our more than 20 years’ experience with the JPHC Study. From 2011 through 2016, a baseline survey was conducted at 16 municipalities in seven prefectures across the country. A self-administered questionnaire was distributed to all registered residents aged 40–74, which mainly asked about lifestyle factors, such as socio-demographic situation, personal medical history, smoking, alcohol and dietary habits. We obtained informed consent from each participant to participate in this long follow-up study of at least 20 years, including consent to the potential use of their residence registry, medical records, medical fee receipts, care insurance etc., and to the provision of biospecimens (blood and urine), including genomic analysis.Results: As of December 31, 2016, we have established a population-based cohort of 115,385 persons (Response rate 44.1%), among whom 55,278 (47.9% of participants) have provided blood and urine samples. The participation rate was slightly higher among females and in the older age group.Conclusion: We have established a large-scale population-based cohort for next-generation epidemiological study in Japan
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