Journal of the Physical Society of Japan
Online ISSN : 1347-4073
Print ISSN : 0031-9015
ISSN-L : 0031-9015
Volume 71, Issue 5
Displaying 1-40 of 40 articles from this issue
  • Kenji Kawamura, Naomichi Hatano
    Article type: General Physics
    Subject area: Mathematical methods in physics.
    2002 Volume 71 Issue 5 Pages 1211-1213
    Published: 2002
    Released on J-STAGE: April 25, 2003
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    We introduce a simple and generic model that reproduces Zipf's law. By regarding the time evolution of the model as a random walk in the logarithmic scale, we explain theoretically why this model reproduces Zipf's law. The explanation shows that the behavior of the model is very robust and universal.
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  • Masato Ida
    Article type: General Physics
    Subject area: Mathematical methods in physics.
    2002 Volume 71 Issue 5 Pages 1214-1217
    Published: 2002
    Released on J-STAGE: April 25, 2003
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    “Transition frequencies” of a system containing an arbitrary number of bubbles levitated in a liquid are discussed. Using a linear coupled-oscillator model, it is shown theoretically that when the system contains N bubbles of different sizes, each bubble has 2N - 1 (or less) transition frequencies which make the phase difference between an external sound and a bubble's pulsation π / 2. Furthermore, we discuss a discrepancy appearing between the present result regarding the transition frequencies and existing ones for the resonance frequencies in a two-bubble case, and show that the transition frequency, defined as above, and the resonance frequency have a different physical meaning when N ≥ 2, while they are consistent for N = 1.
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  • Shinobu Aoyagi, Yoshihiro Kuroiwa, Akikatsu Sawada, Isao Yamashita, To ...
    Article type: General Physics
    Subject area: Mathematical methods in physics.
    2002 Volume 71 Issue 5 Pages 1218-1221
    Published: 2002
    Released on J-STAGE: April 25, 2003
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    The size effects on the crystal structure and phase transitions have been investigated for BaTiO3 fine particles of 700, 400, 300 and 100 nm size, by means of powder diffraction using synchrotron radiation (SR) high-energy X-rays. The Rietveld refinement reveals that the BaTiO3 fine particles consist of tetragonal and cubic structure components at 300 K. The structure model indicating that the cubic BaTiO3 shell covers the tetragonal BaTiO3 core is examined. The thickness of the cubic shell is estimated at approximately 8 nm, which is almost constant irrespective of particle sizes, and the volume ratio of the cubic component increases with decreasing the particle size. Successive phase transitions are detected even in 100 nm size particles, where only the tetragonal component undergoes the phase transition.
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  • Jiro Kitagawa, Tetsuya Sasakawa, Toshiaki Suemitsu, Toshiro Takabatake ...
    Article type: General Physics
    Subject area: Mathematical methods in physics.
    2002 Volume 71 Issue 5 Pages 1222-1225
    Published: 2002
    Released on J-STAGE: April 25, 2003
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    We have found that in the series of R3Pd20X6 (R=rare-earth element, X=Si or Ge), only Eu3Pd20Ge6 shows valence-fluctuating behavior. The Eu atoms are caged in two kinds of polyhedra composed of Pd or Ge atoms, forming a clathrate-like structure. Since a rattling motion of the Eu atoms in the cages was expected, we have assessed the thermoelectric properties of Eu3Pd20Ge6 by measuring its electrical resistivity, thermopower and thermal conductivity. Eu3Pd20Ge6 shows good electrical conductivity. Reflecting the valence-fluctuating state, the thermopower reaches a maximum value of about 10 μV/K around 120 K. The thermal conductivity larger than 10 W/mK at high temperatures indicates a negligible rattling of Eu atoms.
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  • Susumu Yamamoto, Takeo Fujiwara
    Article type: General Physics
    Subject area: Mathematical methods in physics.
    2002 Volume 71 Issue 5 Pages 1226-1229
    Published: 2002
    Released on J-STAGE: April 25, 2003
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    Electronic structures of NdNiO3 and YNiO3 are calculated by using the LSDA+U method with rotational invariance. No orbital order on Ni sites is observed in the calculations for the two systems. Different types of charge ordering are found in the two systems. In a small distorted system NdNiO3, all nickel ions are trivalent, while oxygen sites show charge ordering and spin density polarization in the energy range of Ni eg σ* band. In a large distorted system YNiO3, charge disproportionation occurs. Therefore, the charge ordering stabilizes the asymmetry of the arrangement of Ni magnetic moments in both systems.
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  • Satoshi Fujimoto
    Article type: General Physics
    Subject area: Mathematical methods in physics.
    2002 Volume 71 Issue 5 Pages 1230-1233
    Published: 2002
    Released on J-STAGE: April 25, 2003
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    We investigate pseudogap phenomena realized in the BCS pairing model with a long but finite interaction range. We calculate the single-particle self-energy in all orders exactly in the temperature range where the superconducting fluctuation propagator is Gaussian-like. It is found that vertex corrections to the self-energy, which are discarded in the previous studies, are crucially important for the pseudogap of the single-particle density of states in higher order calculations.
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  • Hiroshi Shimahara, Kentaro Moriwake
    Article type: General Physics
    Subject area: Mathematical methods in physics.
    2002 Volume 71 Issue 5 Pages 1234-1237
    Published: 2002
    Released on J-STAGE: April 25, 2003
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    The upper critical field parallel to the conducting layer is studied in anisotropic type II superconductors on square lattices. We assume sufficient separation of the adjacent layers, for which the orbital pair-breaking effect is suppressed for precisely aligned parallel magnetic fields. In particular, we examine the temperature dependence of the critical field Hc(T) of the superconductivity including the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO or LOFF) state, in which the Cooper pairs have nonzero center-of-mass momentum q. In the system with the cylindrically symmetric Fermi surface, it is known that Hc(T) of the d-wave FFLO state exhibits a kink at a low temperature due to a change in the direction of q in contrast to observations in organic superconductors. It is shown that the kink disappears when the Fermi surface is anisotropic to some extent, since the direction of q is locked in an optimum direction independent of temperature.
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  • Noboru Fukushima, Yoshio Kuramoto
    Article type: General Physics
    Subject area: Mathematical methods in physics.
    2002 Volume 71 Issue 5 Pages 1238-1241
    Published: 2002
    Released on J-STAGE: April 25, 2003
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    Thermodynamic properties of the SU(n) Heisenberg model with the nearest-neighbor interaction in one dimension are studied by means of high-temperature expansion for arbitrary n. The specific heat up to O[(β J)23] and the correlation function up to O[(β J)19] are derived with β J being the antiferromagnetic exchange in units of temperature. The series coefficients are obtained as explicit functions of n. It is found for n>2 that the specific heat exhibits a shoulder on the high-temperature side of a peak. The origin of this structure is clarified by deriving the temperature dependence of the correlation function. With decreasing temperature, the short-range correlation with two-site periodicity develops first, and then another correlation occurs with n-site periodicity at lower temperature. This behavior is in contrast to that of the 1/r2-model, where the specific heat shows a single peak according to the exact solution.
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  • Takeru Suzuki, Hiroshi Imamura, Masahiko Hayashi, Hiromichi Ebisawa
    Article type: General Physics
    Subject area: Mathematical methods in physics.
    2002 Volume 71 Issue 5 Pages 1242-1245
    Published: 2002
    Released on J-STAGE: April 25, 2003
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    We study orbital magnetism in a three-dimensional (3D) quantum dot with a parabolic confining potential. We calculate the free energy of the system as a function of the magnetic field and the temperature. By this, we show that the temperature-field plane can be classified into three regions in terms of the characteristic behavior of the magnetization: the Landau diamagnetism, de Haas-van Alphen oscillation and mesoscopic fluctuation of magnetization. We also calculate numerically the magnetization of the system and then the current density distribution. As for the oscillation of the magnetization when the field is varied, the 3D quantum dot shows a longer period than a 2D quantum dot which contains the same number of electrons. A large paramagnetism appears at low temperatures when the magnetic field is very weak.
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  • Takuma Ohashi, Sei-ichiro Suga
    Article type: General Physics
    Subject area: Mathematical methods in physics.
    2002 Volume 71 Issue 5 Pages 1246-1249
    Published: 2002
    Released on J-STAGE: April 25, 2003
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    We investigate the Kondo effect in two-dimensional disordered electron systems using a finite-temperature quantum Monte Carlo method. Depending on the position of a magnetic impurity, the local moment is screened or unscreened by the spin of the conduction electron. The results suggest that the Kondo temperature takes different values depending on the position of a magnetic impurity. We show that the distribution of the Kondo temperature becomes wide and the weight at TK=0 becomes large as randomness increases. The average susceptibility shows a weak power-law divergence at low temperature in strongly disordered systems, indicating a non-Fermi-liquid behavior. We calculate the correlation function between the local moment and the spin of the conduction electron. The results are discussed in connection with Kondo screening.
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  • Shoji Yamamoto, Tôru Sakai, Akihisa Koga
    Article type: General Physics
    Subject area: Mathematical methods in physics.
    2002 Volume 71 Issue 5 Pages 1250-1253
    Published: 2002
    Released on J-STAGE: April 25, 2003
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    In response to recent attempts to construct higher-spin ladder materials from organic polyradicals, we study the ground-state properties of a wide class of antiferromagnetic spin-1 ladders. Employing various numerical tools, we reveal the rich phase diagram and correct a previous nonlinear-sigma-model prediction. A variational analysis interprets the phase competition well with particular emphasis on the re-entrant phase boundary as a function of the rung interaction.
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  • Masaru Kasahara, Ruiping Wang, Mitsuru Itoh, Toshirou Yagi
    Article type: General Physics
    Subject area: Mathematical methods in physics.
    2002 Volume 71 Issue 5 Pages 1254-1256
    Published: 2002
    Released on J-STAGE: April 25, 2003
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    A detailed study of ferroelectric microregions (FMRs) of SrTi18O3x16O3(1-x) was carried out for x=0.21, 0.47 and 0.99. From the analysis of FMR spectra, the soft mode was found in the paraelectric phase even though the present study could not reveal whether its frequency reaches exactly zero or not. The size of an FMR with x=0.21 becomes larger than those of other species. This result implies that the development of FMRs does not cause the ferroelectric phase transition. It is concluded that the phase transition induced isotopically in SrTiO3 is of the displacive type.
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  • Makoto Kuwata-Gonokami, Ryo Shimano, Andre Mysyrowicz
    Article type: General Physics
    Subject area: Mathematical methods in physics.
    2002 Volume 71 Issue 5 Pages 1257-1260
    Published: 2002
    Released on J-STAGE: April 25, 2003
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    By using femtosecond optical pulses we create and manipulate a long-lived highly coherent biexcitonic wave in CuCl. Phase space compression by a factor 102 in the two-photon absorption process yields a quasiparticle ensemble with a density of up to 1013 cm-3 and more than 104 biexcitons per mode, which shows harmonic scalar wave behavior for 70 ps. The coherent biexciton ensemble acts as a phase-dependent two-photon amplifier for optical pulses. Phase sensitivity of the light pulse transmission allows us to phase lock the two successive pulses and demonstrates the coherent control of biexciton waves. By measuring the visibility of the biexcitonic interference pattern we confirm a high degree of coherence of the stored excitation.
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  • Atsushi Furuya, Sanae-I. Itoh, Masatosi Yagi
    Article type: General Physics
    Subject area: Mathematical methods in physics.
    2002 Volume 71 Issue 5 Pages 1261-1267
    Published: 2002
    Released on J-STAGE: April 25, 2003
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    The dynamics of the magnetic island affected by the microscopic turbulence is analyzed using the renormalized reduced MHD equations. The evolution equations of the island width w(t) and rotation frequency ω(t) are derived in the cold ion approximation. It is found that the effects of the current flowing in a layer close to the separatrix are important to evaluate the effects of turbulent diffusions on the island rotation. As the result, the rotation of the magnetic island is driven by anomalous resistivity, and suppressed by anomalous ion viscosity and thermal conductivity.
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  • Mitsuhiro Kawasaki, Sanae-I. Itoh, Masatoshi Yagi, Kimitaka Itoh
    Article type: General Physics
    Subject area: Mathematical methods in physics.
    2002 Volume 71 Issue 5 Pages 1268-1273
    Published: 2002
    Released on J-STAGE: April 25, 2003
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    Transition phenomena between thermodynamic branch and turbulent branch in submarginal turbulent plasma are analyzed with statistical theory. Time-development of turbulent fluctuation is obtained by numerical simulations of Langevin equation which contains submarginal characteristics. Probability density functions and transition rates between two states are analyzed. Transition from turbulent branch to thermodynamic branch occurs in almost entire region between subcritical bifurcation point and linear stability boundary.
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  • Leonid G. Bruskin, Atsushi Mase
    Article type: General Physics
    Subject area: Mathematical methods in physics.
    2002 Volume 71 Issue 5 Pages 1274-1279
    Published: 2002
    Released on J-STAGE: April 25, 2003
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    The results of analytical solution of the time-dependent 2D full wave equation in cylindrical coordinates are presented here with application to plasma fluctuation reflectometry. We consider a family of plasma density profiles with cylindrical symmetry, which allow for a full integration of the microwave scattering problem in Born approximation. The cylindrical model is more realistic as compared to the 1D stratified plasma models previously employed in all the analytical and most numerical treatments since the plasma in the fusion toroidal devices, mirror machines and plasma processing chambers can often be considered axially symmetric on the scale relevant to microwave reflectometry. Based on the results of analytical modeling, the effects of beam refraction and scattering are studied taking into account possible asymmetry in the antenna alignment. The curvature effects on the microwave reflection and scattering are visualized and compared for the cases of plasma profiles with low and high curvatures. The reflectometer sensitivity to the small radial scale fluctuations is shown to increase in the plasma with the high curvature. Obtained expressions can be applied to the other reflectometry-related issues, such as Doppler reflectometry, phase runaway effect, and the turbulence amplitude estimation.
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  • S. Mori, R. Shoji, N. Yamamoto, A. Machida, Y. Moritomo, T. Katsufuji
    Article type: General Physics
    Subject area: Mathematical methods in physics.
    2002 Volume 71 Issue 5 Pages 1280-1283
    Published: 2002
    Released on J-STAGE: April 25, 2003
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    Impurity effect on the charge and orbital ordered (CO/OO) state in doped manganites has been studied by the transmission electron microscopy (TEM), in addition to the electric and magnetic measurements. In the Cr-doped manganites (Nd0.5Ca0.5Mn1-yCryO3), the CO/OO state characterized by the incommensurate wave vector is still realized as the microdomains with the size of 10-30 nm even at lower temperature of 20 K. On the other hand, the Sc-doped manganites (Nd0.5Ca0.5Mn1-yScyO3) clearly show an incommensurate to commensurate structural phase transition accompanying the formation of the long-ranged CO/OO state around 60 K. From our experimental findings, it is suggested that the substituted Cr3+ and Sc3+ ions serve as the spin impurity and hole vacancy, respectively.
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  • Takeshi Iizuka
    Article type: General Physics
    Subject area: Mathematical methods in physics.
    2002 Volume 71 Issue 5 Pages 1284-1295
    Published: 2002
    Released on J-STAGE: April 25, 2003
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    Dynamics of gap solitons in various kinds of polyatomic chains are analyzed comprehensively. First, we consider a case that the periodic modulation of the anharmonic lattice parameters is small (shallow grating) and obtain coupled mode models between the forward and backward propagating waves at the Bragg wavenumber. Depending on the period of the chain N(>1) and on the nonlinearity, we derive four types of coupled mode equations. Moving localized solutions for gap solitons are obtained analytically. It is found that owing to the quadratic nonlinearity, static dc waves should be taken into account, which leads to the concept of “dynamical rectification”. The theoretical results for gap solitons are checked by numerical simulations. Secondly, we consider the case of large modulation of the lattice parameters (deep grating). We develop a theory of the nonlinearity-induced carrier-wave modulations of the lattice mode dynamics (Bloch wave) and derive the effective nonlinear Schrödinger equation. Numerical simulations of the standing and moving solitons and their collision revealed almost elastic interactions of the gap soliton.
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  • Hideaki Uemura, Makio Uwaha, Yukio Saito
    Article type: General Physics
    Subject area: Mathematical methods in physics.
    2002 Volume 71 Issue 5 Pages 1296-1307
    Published: 2002
    Released on J-STAGE: April 25, 2003
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    We study the equilibrium shape of a heteroepitaxial island with a two-dimensional lattice model, which contains elastic deformation of the lattice and incorporates the effect of a spontaneous stress. For simlicity, the substrate is assumed to be rigid. We calculate phase diagrams of the island shape as a function of the interfacial bond energy γ and the magnitude of the elastic energy g. The aspect ratio of the height to the width decreases as γ increases, while it increases as g increases. This indicates that the larger the aspect ratio, the more the elastic relaxation energy gains. When the island size na increases, the island with a larger aspect ratio becomes more stable. Therefore an island changes into the shape with larger elastic relaxation as na increases. The same result is predicted by the continuum elasticity theory. We calculate the optimum island size as a function of g. The optimum size changes from ∞ to a finite value as g increases.
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  • Katsunori Kubo
    Article type: General Physics
    Subject area: Mathematical methods in physics.
    2002 Volume 71 Issue 5 Pages 1308-1312
    Published: 2002
    Released on J-STAGE: April 25, 2003
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    A model describing orbital degrees of freedom of eg electrons on a cubic lattice is studied at half-filling. The orbital degrees of freedom can be described by pseudospins, and the ground state and the excitation spectrum of the effective Hamiltonian in the strong coupling limit are studied. It is found that a pseudospin ordered state is realized at finite temperatures with the help of the quantum fluctuations, which yield a finite gap in the purely two-dimensional excitation spectrum.
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  • Zhimei Sun, Yanchun Zhou
    Article type: General Physics
    Subject area: Mathematical methods in physics.
    2002 Volume 71 Issue 5 Pages 1313-1317
    Published: 2002
    Released on J-STAGE: April 25, 2003
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    The crystal structure, electronic structure and chemical bonding of Ti4AlN3 have been investigated by ab initio pseudopotential calculations. The equilibrium lattice parameters, atomic positions in the unit cell and bond lengths have been obtained by minimizing the total energy. The differences between the calculated and measured lattice constants are generally less than 1%. The electronic structure of Ti4AlN3 shows a metallic-like character and the 3d states of Ti dominate its electronic conductivity. The chemical bonding in Ti4AlN3 is an anisotropic metallic-covalent-ionic character. TiI,II and N atoms form strong covalent ionic bond in the TiII-NII-TiI-NI-TiI-NII-TiII-Al unit chain, while the bonding between TiII and Al is relatively weak. The strong covalent and ionic bonding in Ti4AlN3 is responsible for its high modulus and strength, while the metallic bonding results in its metallic properties. This kind of anisotropic bonding character results in the anisotropic properties of Ti4AlN3.
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  • Tsuneya Ando, Yisong Zheng, Hidekatsu Suzuura
    Article type: General Physics
    Subject area: Mathematical methods in physics.
    2002 Volume 71 Issue 5 Pages 1318-1324
    Published: 2002
    Released on J-STAGE: April 25, 2003
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    A topological anomaly present at zero energy is shown to give rise to a peculiar and singular behavior of the dynamic and static conductivity in two-dimensional honeycomb lattices. A calculation in a self-consistent Born approximation reveals that this singular dependence prevails although being somewhat smoothed out even if level broadening effects are taken into account.
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  • M.-E. Pistol
    Article type: General Physics
    Subject area: Mathematical methods in physics.
    2002 Volume 71 Issue 5 Pages 1325-1331
    Published: 2002
    Released on J-STAGE: April 25, 2003
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    We have found the equations that determine the self-adjoint extensions, and thus the boundary conditions, of the differential operator used in the multi-band k·p-theory, when the coefficients in the Kane-matrix are piecewise constant. Both the one-dimensional and the three-dimensional case have been investigated. A numerical calculation shows that the choice of boundary conditions affects the energy eigenvalues for a quantum well.
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  • Jing-Lin Xiao Eerdunchaolu, Wei Xiao
    Article type: General Physics
    Subject area: Mathematical methods in physics.
    2002 Volume 71 Issue 5 Pages 1332-1338
    Published: 2002
    Released on J-STAGE: April 25, 2003
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    Taking into account the interaction of an electron with both the weak-coupling bulk longitudinal optical (LO) and the strong-coupling surface optical (SO) phonons, we study the magnetic field and temperature dependence of the mass of a surface magnetopolaron in polar crystals by using a linear combination operator method. Numerical calculations, for an AgBr crystal, as an example, are performed, and the magnetic field and temperature characteristics of the mass of the surface magnetopolaron are discussed.
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  • J. X. Cao, X. H. Yan, J. W. Ding, D. L. Wang, Di Lu
    Article type: General Physics
    Subject area: Mathematical methods in physics.
    2002 Volume 71 Issue 5 Pages 1339-1345
    Published: 2002
    Released on J-STAGE: April 25, 2003
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    By introducing the sp3s* tight-binding model, the band structure and electronic density of states of single-walled carbon nanotubes are calculated. It is found that “metallic” zigzag single-walled carbon nanotubes open gaps about 7 meV-0.2 eV near Fermi level. In addition, the changes of diameter and chiral angles plays important roles in electronic properties of carbon nanotubes, especially of small-diameters tubes.
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  • Jun'ya Hori, Shingo Iwata, Hiromi Kurisaki, Fumihiko Nakamura, Takashi ...
    Article type: General Physics
    Subject area: Mathematical methods in physics.
    2002 Volume 71 Issue 5 Pages 1346-1352
    Published: 2002
    Released on J-STAGE: April 25, 2003
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    To investigate the correlation between the high-Tc superconductivity and two-dimensional metallic properties, the in-plane resistivity ρab of La2-xSrxCuO4 (LSCO) with x=0.06, 0.07, 0.08 and 0.22 has been measured under anisotropic high pressures up to 8.0 GPa. Although high pressure suppresses the orthorhombic distortion so as to contribute positively to Tc, the inter-layer compression was found to bring about a kind of localization in the electronic state of the two-dimensional CuO2 planes in the under-doped region. The collapse of two-dimensional metallic state probed by ρab was confirmed to cause the superconductor-insulator transition in the under-doped cuprates. On the other hand, the overdoped cuprates lose superconductivity when the electronic structure changes from the two-dimensional metallic one to a strongly anisotropic but three-dimensional Fermi liquid system. The temperature dependence of ρab is discussed in details in conjunction with Tc both for the under-doped and overdoped LSCO.
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  • Jun Kondo
    Article type: General Physics
    Subject area: Mathematical methods in physics.
    2002 Volume 71 Issue 5 Pages 1353-1359
    Published: 2002
    Released on J-STAGE: April 25, 2003
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    Superconductivity arising from coulomb repulsion between electrons has been studied for a multiband system. We consider on-site and inter-site coulomb integrals, inter-site exchange integrals and inter-site exchange-like integrals [K of eq. (42)]. We do not take account of the correlation effect caused by the interaction, such as spin fluctuation etc., and calculate the average of the interaction energy with the BCS wave function. We find that when K is so large that satisfies eq. (50), an s-type superconducting state is stable when there are two fermi surfaces. The gap functions on these fermi surfaces have different signs and so the pair transition between them gives us a negative energy for a positive K, leading to superconductivity.
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  • Tadashi Fukuhara, Hiroaki Kadowaki, Naofumi Aso, Tetsuya Takeuchi, Tom ...
    Article type: General Physics
    Subject area: Mathematical methods in physics.
    2002 Volume 71 Issue 5 Pages 1360-1364
    Published: 2002
    Released on J-STAGE: April 25, 2003
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    The magnetic structure of heavy-fermion antiferromagnets Ce(Ni1-xPdx)2Ge2 proximate to the magnetic instability has been studied by elastic neutron scattering using single crystals. For Ce(Ni0.65Pd0.35)2Ge2, antiferromagnetic ordering with an incommensurate propagation vector q=(1/2,1/2,δ); δ∼ 0.16 is observed below TN=3.4 K. The integrated intensities of magnetic Bragg peaks at 1.8 K are well fitted by assuming a sine-wave-modulated structure with the amplitude 0.55± 0.04 μB and magnetic moments along [110]. For the compound very near the magnetic instability, Ce(Ni0.90Pd0.10)2Ge2, the ordered moment is expected to be reduced to below 0.1 μB.
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  • Naoyuki Tateiwa, Tatsuo C. Kobayashi, Kiichi Amaya, Dexin LI, Yoshinob ...
    Article type: General Physics
    Subject area: Mathematical methods in physics.
    2002 Volume 71 Issue 5 Pages 1365-1369
    Published: 2002
    Released on J-STAGE: April 25, 2003
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    Low-temperature specific heat and its field-dependence up to 16 T was measured in a stoichiometric single crystal of YbP. A sharp peak was observed at TN = 0.53 K in zero magnetic field. Application of external field seems to induce a new magnetic phase above 11 T. The field dependence of the transition temperature in the high-field phase is different from that of the low field phase. The linear coefficient of the electronic specific heat is estimated as 120 mJ/mol·K2 from low temperature specfic heat, suggesting heavy Fermion state in YbP.
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  • Hisaaki Tanaka, Kazuhiro Marumoto, Shin-ichi Kuroda, Toshio Manabe, Ma ...
    Article type: General Physics
    Subject area: Mathematical methods in physics.
    2002 Volume 71 Issue 5 Pages 1370-1375
    Published: 2002
    Released on J-STAGE: April 25, 2003
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    ESR measurements have been performed on single crystals of the quasi-one-dimensional halogen-bridged mixed-metal complexes Ni1-xPdx(chxn)2Br3, where on-site Coulomb interaction (Ni3+ case) and electron-phonon interaction (Pd2+-Pd4+ case) are competing with each other. Monotonic decrease of principal g-values from gmaxNi = 2.188 to gmaxPd = 2.133 was observed as x increases. This indicates that the magnetic Pd3+ ions with smaller g-value than that of Ni3+ are induced from non-magnetic Pd2+-Pd4+ chain, which is consistent with the previously observed spin susceptibility enhancement in this system. In addition, monotonic decrease of the ESR linewidth is observed as x increases indicating the contribution of Pd3+ ions with longer spin-lattice relaxation time T1D, which is supported by using isomorphic chlorine complexes Ni(chxn)2Cl3 and Pd(chxn)2Cl3.
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  • Kazuo Gesi
    Article type: General Physics
    Subject area: Mathematical methods in physics.
    2002 Volume 71 Issue 5 Pages 1376-1380
    Published: 2002
    Released on J-STAGE: April 25, 2003
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    Phase transitions in [P(CH3)4]2CuY4 (Y = Cl, Br) have been studied by dielectric measurements. In [P(CH3)4]2CuCl4, a slight break and a discontinuous jump on the dielectric constant vs. temperature curve are seen at the normal-incommensurate and the incommensurate-commensurate phase transitions, respectively. A small peak of dielectric constant along the b-direction exists just above the incommensurate-to-commensurate transition temperature. The anisotropic dielectric anomalies of [P(CH3)4]2CuBr4 at phase transitions were measured along the three crystallographic axes. The pressure-temperature phase diagram of [P(CH3)4]2CuCl4 was determined. The initial pressure coefficients of the normal-to-incommensurate and the incommensurate-to-commensurate transition temperatures are 0.19 K/MPa and 0.27 K/MPa, respectively. The incommensurate phase in [P(CH3)4]2CuCl4 disappears at a triple point which exists at 335 MPa and 443 K. The stability and the pressure effects of the incommensurate phases are much different among the four [Z(CH3)4]2CuY4 crystals (Z = N, P; Y = Cl, Br).
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  • Tomoe Ikawa, Kikuo Cho
    Article type: General Physics
    Subject area: Mathematical methods in physics.
    2002 Volume 71 Issue 5 Pages 1381-1392
    Published: 2002
    Released on J-STAGE: April 25, 2003
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    Combining the two enhancement mechanisms of radiation-matter interaction, one in long wavelength regime (LWR) and the other via resonant Bragg reflection, we systematically studied the coupling strengths of various arrays of resonant units. As a general measure of the coupling strength, the radiative width of each resonance was calculated according to the first-principles theory of microscopic nonlocal response of matter. A numerical study was carried out for three resonant Bragg arrangements of (A) N atoms, (B) N chains of atoms, and (C) N planes of atoms. Different aspects of enhancement are clarified as the size-linear increase in LWR and its dimensionality dependence, the speed-up effect of decay, and the super-enhancement effect due to all these mechanisms in case (C) with its saturation behavior for large N.
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  • Shinya Wakoh, Maki Tokii, Makoto Matsumoto, Isao Matsumoto
    Article type: General Physics
    Subject area: Mathematical methods in physics.
    2002 Volume 71 Issue 5 Pages 1393-1400
    Published: 2002
    Released on J-STAGE: April 25, 2003
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    Directional magnetic Compton-profiles of simple cubic Fe3Pt alloy are calculated by the full potential linearized augmented-plane-wave (FLAPW) method coded in WIEN97 and a linear tetrahedron method for the two dimensional integration. They are compared with experimental ones. Similarly to the situation for the element metals, the theoretical Compton profiles which are based upon independent-particle model (IPM) are a little greater than the experimental ones around the origin of the momentum space.
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  • Michihiro Shibata, Terumasa Shindou, Akihiro Taniguchi, Yasuaki Kojima ...
    Article type: General Physics
    Subject area: Mathematical methods in physics.
    2002 Volume 71 Issue 5 Pages 1401-1402
    Published: 2002
    Released on J-STAGE: April 25, 2003
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  • Jun Goryo, Mahito Kohmoto
    Article type: General Physics
    Subject area: Mathematical methods in physics.
    2002 Volume 71 Issue 5 Pages 1403-1404
    Published: 2002
    Released on J-STAGE: April 25, 2003
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  • Kenichi Yamanaka, Atsushi Suzuki, Morio Suzuki
    Article type: General Physics
    Subject area: Mathematical methods in physics.
    2002 Volume 71 Issue 5 Pages 1405-1406
    Published: 2002
    Released on J-STAGE: April 25, 2003
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  • Dai S. Hirashima
    Article type: General Physics
    Subject area: Mathematical methods in physics.
    2002 Volume 71 Issue 5 Pages 1407-1408
    Published: 2002
    Released on J-STAGE: April 25, 2003
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  • Koichi Nakamura, Keisuke Motoki, Yoshitaka Michihiro, Tatsuo Kanashiro ...
    Article type: General Physics
    Subject area: Mathematical methods in physics.
    2002 Volume 71 Issue 5 Pages 1409-1410
    Published: 2002
    Released on J-STAGE: April 25, 2003
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  • Yoshiyuki Matsumoto
    Article type: General Physics
    Subject area: Mathematical methods in physics.
    2002 Volume 71 Issue 5 Pages 1411-1412
    Published: 2002
    Released on J-STAGE: April 25, 2003
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  • Takahiro Sunaga, Midori Tanaka, Nobuhiko Sakai, Yorihiko Tsunoda
    Article type: General Physics
    Subject area: Mathematical methods in physics.
    2002 Volume 71 Issue 5 Pages 1413
    Published: 2002
    Released on J-STAGE: April 25, 2003
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