-
Hirohito Kiwata, Yasuhiro Akutsu
1992 Volume 61 Issue 7 Pages
2161-2164
Published: July 15, 1992
Released on J-STAGE: June 01, 2007
JOURNAL
RESTRICTED ACCESS
For the integrable long-range SU(
M) spin chain, the exact ground-state wave function is constructed for arbitrary irreducible representation of the permutation group.
View full abstract
-
Masataka Mizushima
1992 Volume 61 Issue 7 Pages
2165-2168
Published: July 15, 1992
Released on J-STAGE: June 01, 2007
JOURNAL
RESTRICTED ACCESS
Because the solar system is orbiting around the center of the Milky Way galaxy with a speed of about 220 km/s, I showed, in a previous paper (M. Mizushima: J. Phys. Soc. Jpn.
61 (1992)1125), that
gxx−
gyy=
gxx−
gzz=10
−12, where
gij is the metric for an observer moving with the solar system, and the
x-axis is in the direction of the orbiting velocity of the solar system, namely, in the direction of constellation Cygnus. To detect any anisotropy of space, Brillet and Hall placed an interferometer on a turntable which rotated in a horizontal plane, and they tried to detect any change in size of a cavity optically. They could detect fractional change of the cavity size to 0.5×10
−14, but they did not find any anisotropy of space (A. Brillet and J. L. Hall: Phys. Rev. Lett.
42 (1979) 549). It is shown here that the reason why they did not observe anisotropy of space was that they mounted the interferometer cavity too rigidly on the turntable.
View full abstract
-
T. Schneider, A. Schmidt
1992 Volume 61 Issue 7 Pages
2169-2172
Published: July 15, 1992
Released on J-STAGE: June 01, 2007
JOURNAL
RESTRICTED ACCESS
Using finite size scaling we relate the fall of the transition temperature with reduced thickness to the temperature dependence of the bulk superfluid density and the amplitude of the perpendicular phase correlation length. The scaling predictions agree quantitatively with Monte Carlo estimates of the
xy-model and experiments on
4He films. We also investigate the behavior of the helicity modulus for different system thickness, showing the crossover from the universal Kosterlitz-Thouless jump to the three-dimensional behavior.
View full abstract
-
Takamichi Terao, Kousuke Yakubo, Tsuneyoshi Nakayama
1992 Volume 61 Issue 7 Pages
2173-2177
Published: July 15, 1992
Released on J-STAGE: June 01, 2007
JOURNAL
RESTRICTED ACCESS
The asymptotic behavior of localized wave functions of fractons and electrons in
bond-percolation systems is investigated numerically by calculating the system-size dependence of the conductance. It is found that two-dimensional (2
d) fracton wave functions are superlocalized with
dφ=1.26±0.02, where
dφ is the exponent indicating the strength of localization, while localized electronic states in 2
d percolation systems decay exponentially (
dφ=1).
View full abstract
-
Masaru Shinohara
1992 Volume 61 Issue 7 Pages
2178-2181
Published: July 15, 1992
Released on J-STAGE: May 29, 2007
JOURNAL
RESTRICTED ACCESS
An experimental study has been conducted on the lateral velocity of a spherical rigid particle sedimenting inside of a vertical cylinder. The lateral velocity was obtained by measuring the trajectories of the particles. In this investigation, the ratio of the cylinder diameter to the particle diameter is in the range 0.01–0.04 and the particle Reynolds number is in the range 0.03–0.30. The experimentally determined lateral velocity is found to be in good agreement with the theory.
View full abstract
-
Kozo Hoshino, Hideaki Ugawa, Mitsuo Watabe
1992 Volume 61 Issue 7 Pages
2182-2185
Published: July 15, 1992
Released on J-STAGE: June 01, 2007
JOURNAL
RESTRICTED ACCESS
We have investigated the temperature dependence of the dynamical structure, in particular the dispersion relation of the collective excitation, of expanded liquid rubidium on the basis of the effective pair potential derived by the pseudopotential theory, the static structure factor calculated in the modified hypernetted-chain (MHNC) approximation and the dynamical structure factor in the viscoelastic approximation. The characteristic features of the observed temperature dependence of the dispersion relation are well reproduced theoretically.
View full abstract
-
Kazunari Hori, Shozo Takeno
1992 Volume 61 Issue 7 Pages
2186-2189
Published: July 15, 1992
Released on J-STAGE: June 01, 2007
JOURNAL
RESTRICTED ACCESS
A numerical experiment and an analytical calculation are made to study self-localized modes for the displacement field of a pure one-dimensional lattice with hard quartic anharmonicity. Approximate analytical solutions are obtained for moving localized modes with eigenfrequencies above the top of the harmonic frequency band. The envelope of the displacement field itself is of the form of the conventional sech function, depending on the wave vector of carrier waves. By using approximate analytical solutions as input, numerical experiments are made to explore the space-time evolution of the localized modes by taking the localized mode height and the wave vector of carrier waves as parameters. It is shown that the moving localized modes obtained here are identifiable as lattice solitons under favorable conditions.
View full abstract
-
Shigefumi Onodera
1992 Volume 61 Issue 7 Pages
2190-2193
Published: July 15, 1992
Released on J-STAGE: May 29, 2007
JOURNAL
RESTRICTED ACCESS
From an analysis of X-ray diffraction lines of fine Cu and Ag particles covered with thin oxide surface layers, the dependence of the lattice parameters on particle size in the core of the particles was determined. The lattice parameter particularly in fine Ag particles increases with decreasing particle size when the diameter is under 150 Å. This experimental result can be interpreted in terms of the competition between the lattice softening and the surface tension in the ultrafine particles.
View full abstract
-
Hikaru Terauchi, Yukiho Watanabe, Hirofumi Kasatani, Kosei Kamigaki, Y ...
1992 Volume 61 Issue 7 Pages
2194-2197
Published: July 15, 1992
Released on J-STAGE: May 29, 2007
JOURNAL
RESTRICTED ACCESS
Epitaxial crystals of BaTiO
3 with the thicknesses of 67 Å, 230 Å, 600 Å and 1500 Å were grown on SrTiO
3 substrates by activated reactive evaporation. The tetragonality of the crystal decreases with increasing thickness and remains in the temperature range of 15 K to 670 K. The epitaxial effect is discussed in terms of a critical thickness, as well as of a surface layer of fine particles.
View full abstract
-
Yukinori Ohta, Wataru Koshibae, Sadamichi Maekawa
1992 Volume 61 Issue 7 Pages
2198-2201
Published: July 15, 1992
Released on J-STAGE: June 01, 2007
JOURNAL
RESTRICTED ACCESS
The
63Cu nuclear quadrupole resonance (NQR) frequency of a variety of high-
Tc cuprates is analyzed by a cluster model to examine the origin of the electronic field gradient and its implications on the electronic ground state of the CuO
2 plane. It is shown that a primary contribution from the Cu 3
d(
x2−
y2) hole is cancelled largely by the contribution from the Cu 4
p(
x,
y) electrons, and this cancellation explains both the large material dependence of the frequency in the insulating phase and an extremely small frequency observed in the electron-doped cuprates. Measured NQR frequencies thus provide rich information on the ground-state charge distribution in the CuO
2 plane.
View full abstract
-
Tadaei Ito, Masafumi Shirai, Kazuko Motizuki
1992 Volume 61 Issue 7 Pages
2202-2205
Published: July 15, 1992
Released on J-STAGE: May 29, 2007
JOURNAL
RESTRICTED ACCESS
Self-consistent APW band calculations are carried out for Cu
2Sb intermetallic compound with Cu
2Sb-type structure. The energy dispersion, density of states and Fermi surface are shown. Differences and similarities of the electronic band structures between Cu
2Sb and other Cu
2Sb-type compounds are clarified.
View full abstract
-
Tadao Kasuya
1992 Volume 61 Issue 7 Pages
2206-2208
Published: July 15, 1992
Released on J-STAGE: June 01, 2007
JOURNAL
RESTRICTED ACCESS
The Wigner crystal formation of the neutral electron-hole pair in semimetals such as LaSb was studied by using a simplified phenomenological effective Hamiltonian model. It was shown that before the band gap closes, the transition to the Wigner crystal with a finite number of pairs occur but it resembles the Wigner crystal liquid. As the overlap between two bands increases, it changes to the usual band state with the Coulomb effect. Various puzzling properties in La-monopnictides as well as Ce-monopnictides can be explained by this model.
View full abstract
-
Takuo Sakon, Noriaki Sato, Akira Oyamada, Naoya Takeda, Takashi Suzuki ...
1992 Volume 61 Issue 7 Pages
2209-2211
Published: July 15, 1992
Released on J-STAGE: May 29, 2007
JOURNAL
RESTRICTED ACCESS
Low-temperature specific heat of YbAs has been measured down to about 50 mK. In the antiferromagnetic ordered state (
TN∼0.5 K), the nuclear contribution is observed below about 150 mK. By subtraction of this contribution from the measured specific heat, the linear coefficient of the electronic specific heat is estimated to be about 270 mJ/K
2 mole. This value is extraordinarily large because the carrier concentration in YbAs is of the order of 0.01 per formula unit. This large mass enhancement may be ascribed to a mutual 4f-spin compensation mechanism instead of the usual Kondo spin fluctuation. We also show that the magnetic field effect on the specific heat is rather small.
View full abstract
-
Yutaka Maniwa, Takayuki Shibata, Kenji Mizoguchi, Kiyoshi Kume, Koichi ...
1992 Volume 61 Issue 7 Pages
2212-2215
Published: July 15, 1992
Released on J-STAGE: June 01, 2007
JOURNAL
RESTRICTED ACCESS
Iodine intercalated C
60, I
2.29C
60, was studied by
13C NMR above 160 K. A sharp NMR signal and a strong temperature-dependent spin-lattice relaxation time,
T1, indicated a presence of C
60 molecular rotation much higher than 10 kHz at least down to 160 K. No evidence of metallic characteristics was found in the NMR shift (143±1 ppm) and the
T1 (40±5 sec at room temperature). In K
3C
60, metallic behavior,
T1T∼constant, was observed at the carbon sites between 20 K and 100 K. Electronic density of states at the Fermi level,
N(
EF), in I
2.29C
60 was estimated to be smaller than 0.12 of that in K
3C
60, assuming a relationship between
N(
EF) and
T1T for normal metals.
View full abstract
-
Kazushige Machida, Yoshiki Hori
1992 Volume 61 Issue 7 Pages
2216-2219
Published: July 15, 1992
Released on J-STAGE: June 01, 2007
JOURNAL
RESTRICTED ACCESS
It is argued that the reentrant phenomenon from the field-induced spin density wave state to the normal state at
H≅25 T and the unidentified new high-field phase found in (TMTSF)
2ClO
4 can both be understood consistently within the framework of the so-called standard model and theory. We present detailed discussions in support of this argument by examining various experimental data and evaluating the phase diagram. A missing transition line in still higher fields is predicted.
View full abstract
-
Minoru Fukui, Makoto Iwata, Taturu Yosida, Yoshihiro Ishibashi
1992 Volume 61 Issue 7 Pages
2220-2223
Published: July 15, 1992
Released on J-STAGE: May 29, 2007
JOURNAL
RESTRICTED ACCESS
Dielectric dispersion of a Haldane compound nickel trimethylenediamine nitrite perchlorate Ni(C
3H
10N
2)
2NO
2ClO
4 (NINO) has been measured around the structural phase transition at 378.5 K. The dielectric constant varies like a step at the phase transition and the dielectric dispersion of Debye type was observed along an axis perpendicular to the electrically polar axis above
Tc.
View full abstract
-
Takehisa Yoshinari, Takao Nanba, Shigetaka Shimanuki, Masami Fujisawa, ...
1992 Volume 61 Issue 7 Pages
2224-2226
Published: July 15, 1992
Released on J-STAGE: May 29, 2007
JOURNAL
RESTRICTED ACCESS
The reflection spectra of (C
nH
2n+1NH
3)
2CuCl
4 (
n=1, 2, 3) were measured in the photon energy region of 2.6–25 eV at room temperature (RT) and liquid nitrogen temperature (LNT) by means of synchrotron radiation. The absorption peak at around 3.3 eV (LNT) has a doublet structure and the splitting energy is 0.08 eV, which is the same magnitude as the spin-orbit splitting of a chlorine atom. The band is assigned as an electronic transition from the chlorine 3
p valence band to the copper 4
s lowest conduction band.
View full abstract
-
Junji Watanabe, Hiroyuki Arai, Taihei Nouchi, Jun’ichir\={o} Nak ...
1992 Volume 61 Issue 7 Pages
2227-2230
Published: July 15, 1992
Released on J-STAGE: June 01, 2007
JOURNAL
RESTRICTED ACCESS
Photoluminescence spectra of Mn
2+-related transition assigned as
4T
1–
6A
1 in Cd
1−xMn
xTe (
x=0.4 to 0.7) are investigated in a temperature range from 10 K to 220 K and under hydrostatic pressures up to 20 kbar. The observed temperature dependence of the spectral width shows that in the low-temperature region (10 K to 80 K) a configuration coordinate model is adopted, but in the high-temperature region, using the model, there is deviation from the calculated results. We consider that the equilibrium position
Q0 in the excited states changes toward that in the ground state increasing temperature above 80 K. In addition, anomalous behavior in the temperature dependence of the pressure coefficient of the luminescence peak energy is observed at about 80 K, which is related to the change of
Q0.
View full abstract
-
Jan Awrejcewicz, Tsuneo Someya
1992 Volume 61 Issue 7 Pages
2231-2234
Published: July 15, 1992
Released on J-STAGE: June 01, 2007
JOURNAL
RESTRICTED ACCESS
An analytical condition for the existence of a two-parameter family of quasiperiodic orbits in a
n-dimensional autonomous dynamical system is developed. This condition is based on asymptotic and averaging methods, where two independent perturbation parameters are applied.
View full abstract
-
Takeshi Iizuka, Miki Wadati
1992 Volume 61 Issue 7 Pages
2235-2240
Published: July 15, 1992
Released on J-STAGE: June 01, 2007
JOURNAL
RESTRICTED ACCESS
Nonlinear wave propagations in one-dimentional inhomogeneous lattices are studied. The force between adjacent particles is anharmonic and the mass distrubution is not uniform. It is assumed that the amplitudes of the waves are small and the variation of the mass distribution is slow. By introducing appropriate transformation of independent and dependent variables, we obtain nonlinear evolution equations for various types, strength and slowness, of inhomogeneities. As an application the influences of impurity and discontinuity on the wave propagation are discussed. Our approach is valid for a large class of nonlinear dispersive inhomogeneous systems.
View full abstract
-
Miki Wadati, Takeshi Iizuka, Masato Hisakado
1992 Volume 61 Issue 7 Pages
2241-2245
Published: July 15, 1992
Released on J-STAGE: June 01, 2007
JOURNAL
RESTRICTED ACCESS
A coupled nonlinear Schrödinger equation is studied. The equation describes nonlinear modulations of two monochromatic waves whose group velocities are almost equal. As a special case, optical solitons for two linearly polarlized waves are explicitly shown.
View full abstract
-
Hideo Tsuru
1992 Volume 61 Issue 7 Pages
2246-2256
Published: July 15, 1992
Released on J-STAGE: June 01, 2007
JOURNAL
RESTRICTED ACCESS
A motion of a Gaussian wave packet of a single electron in a uniform magnetic field is obtained by solving the time dependent Schrödinger equation analytically. The wave packet moves changing its width and central position periodically. The period of the change of the width is the same as that of the central position. The interpretation of these periodic changes in terms of the Green’s function which can be derived by the path integration formulation is also discussed.
View full abstract
-
Il-Tong Cheon
1992 Volume 61 Issue 7 Pages
2257-2259
Published: July 15, 1992
Released on J-STAGE: May 29, 2007
JOURNAL
RESTRICTED ACCESS
Cavity QED is applied to the nucleus. The gamma-ray energy is shifted by an order of magnitude 10
−8∼10
−9 eV when the nucleus is placed between two metallic conducting parallel plates separated from each other by 1 mm. This may be measured by the Mössbauer method.
View full abstract
-
Masaru Sugiyama
1992 Volume 61 Issue 7 Pages
2260-2268
Published: July 15, 1992
Released on J-STAGE: June 01, 2007
JOURNAL
RESTRICTED ACCESS
Basic equations which describe, in a unified way, nonequilibrium phenomena in a crystalline lattice are proposed by extending the self-consistent Einstein model to a dynamical one. Gaussian and one-body approximations for a probability distribution function of a lattice are made in the course of the derivation of the equations. In order to emphasize the essential idea of the derivation, only a one-dimensional anharmonic lattice is studied. The present paper, which is the first one of the present series of papers, forms the foundation of the series, since some applications and extensions of the basic equations derived here will be done in subsequent papers.
View full abstract
-
Masaru Sugiyama, Toshio Fukuta
1992 Volume 61 Issue 7 Pages
2269-2279
Published: July 15, 1992
Released on J-STAGE: June 01, 2007
JOURNAL
RESTRICTED ACCESS
By linearizing the basic equations derived in the preceding paper of the present series, nonequilibrium phenomena in a crystalline lattice at a finite temperature are studied. Time evolution of a distribution function for the phenomena can be classified into three characteristic ones. The first corresponds to an elastic wave in a lattice. Its mechanical and thermal properties, that is, dispersion relation, propagation velocities, amplitude ratios, average energy, and entropy are investigated. Some properties of the wave near a melting point are also discussed. Further, physical meanings of the two remainder are also discussed in detail, and a possible connection of these with conduction of heat is pointed out.
View full abstract
-
Masakazu Ichiyanagi
1992 Volume 61 Issue 7 Pages
2280-2286
Published: July 15, 1992
Released on J-STAGE: June 01, 2007
JOURNAL
RESTRICTED ACCESS
The variation principle by Nakano in the quantum theory of transport processes is reformulated in the form of Hamilton’s principle in classical mechanics, which provides us with a new possibility of studying nonequilibrium steady states if we can distinguish the phenomenological currents from the driving forces. From the form of the variation principle, Nakano’s variation principle becomes evident by inspection.
View full abstract
-
Kazuo Sakai, Satoshi Takeuchi, Michio Matsumoto
1992 Volume 61 Issue 7 Pages
2287-2293
Published: July 15, 1992
Released on J-STAGE: June 01, 2007
JOURNAL
RESTRICTED ACCESS
Relativistic particle dynamics is studied analytically and numerically in the electrostatic wave propagating obliquely to the uniform static magnetic field. The criterion is obtained that there exist the particles which keep trapped if the ratio of the field strength of the electrostatic wave to that of the static magnetic field is greater than the critical value which is a function of the propagation angle and the phase velocity of the electrostatic wave. The trapped particles can be accelerated unlimitedly if the propagation angle is larger than the angle which is determined from the phase velocity. The maximum acceleration gradient is also obtained as a function of the field strength, the phase velocity and the propagation angle of the wave.
View full abstract
-
Kimitaka Itoh, Heiji Sanuki, Sanae-I. Itoh
1992 Volume 61 Issue 7 Pages
2294-2303
Published: July 15, 1992
Released on J-STAGE: June 01, 2007
JOURNAL
RESTRICTED ACCESS
Theoretical model is developed to determine the radial electric field and the fast ion loss simultaneously in stellarators, and is applied to the Wendelstein VII-A stellarator. The predicted value of the radial electric field is more closer to experiments than the purely neoclassical calculation. The loss rate, which is determined simultaneously, is in the range of experimental observations. The partition of the injection energy by the bulk heating, direct orbit loss and shine through is estimated by using the selfconsistent electric field profile. The orbit loss becomes noticeable as the injection energy increases. The influence of the neutral particles is also studied. Neutral particles enhance the negative radial electric field, and reduce the direct orbit loss by the expense of the charge exchange loss. The impact of the increased radial electric field on the neoclassical ion thermal energy loss is compared to the direct loss of fast ions. The reduction of the neoclassical loss is much smaller than the orbit loss.
View full abstract
-
Taturu Yosida, Minoru Fukui
1992 Volume 61 Issue 7 Pages
2304-2308
Published: July 15, 1992
Released on J-STAGE: May 29, 2007
JOURNAL
RESTRICTED ACCESS
The crystal structure of nickel trimethylenediamine nitrite perchlorate Ni(C
3H
10N
2)
2NO
2ClO
4 (NINO) has been studied by single-crystal X-ray diffraction. The space group symmetry (
Pbn2
1:
ba\bar
c setting of
Pna2
1) and structure parameters were determined at 23°C with
R=0.035 for 1734 observed reflections. The difference between the structures of NINO and Ni(C
2H
8N
2)
2NO
2ClO
4 (NENP) is discussed. The origin of the spontaneous electric polarization in NINO is also discussed.
View full abstract
-
Hirofumi Kasatani, Takashi Umeki, Hikaru Terauchi
1992 Volume 61 Issue 7 Pages
2309-2316
Published: July 15, 1992
Released on J-STAGE: June 01, 2007
JOURNAL
RESTRICTED ACCESS
X-ray scattering experiments of lead orthovanadate, Pb
3(VO
4)
2, were carried out above and below the ferroelectric transition temperature
T2=273 K, using a monodomain crystal. The space groups were confirmed to be
C2h5-
P2
1⁄
c and
C23-
A2 above and below
T2, respectively. The structure analyses were conducted at several temperatures in both phases. The R-factors were less than 0.060 above
T2 and 0.045 below
T2. The spontaneous polarizations were calculated from the atomic positions in the ferroelectric phase and compared with the values observed by the pyroelectric measurement by Midorikawa
et al. The mechanism of the ferroelectric phase transition is discussed in terms of the mode of atomic displacements.
View full abstract
-
Kikujiro Ishii, Hideyuki Nakayama, Takayuki Sakato, Hironobu Kano
1992 Volume 61 Issue 7 Pages
2317-2326
Published: July 15, 1992
Released on J-STAGE: June 01, 2007
JOURNAL
RESTRICTED ACCESS
Temperature dependences of polarized Raman spectra and birefringence of bis(4-chlorophenyl)sulfone (BCPS) crystal were measured. Gas-phase Raman spectra of BCPS were also measured. Raman bands observed in the low-frequency region at room temperature were shown to have partial nature of intramolecular vibrations. The lowest-frequency Raman band observed at low temperatures softened as the temperature was raised up to
T1=150 K. A gradual change of birefringence was also observed below
T1. These are in harmony with previous reports on the normal-incommensurate phase transition of this crystal at
T1. The critical exponents for the changes in the soft-mode frequency and the birefringence were compared with that for the previously reported intensity change of the satellite X-ray diffraction. These data were explained by assuming an incommensurate orientational modulation of the phenyl groups of BCPS molecules. However, the incommensurate-commensurate transition which has been expected to take place around 115 K was not detected by the present measurements.
View full abstract
-
Masae Yasui, Mitsugu Matsushita
1992 Volume 61 Issue 7 Pages
2327-2332
Published: July 15, 1992
Released on J-STAGE: May 29, 2007
JOURNAL
RESTRICTED ACCESS
Dendritic crystals of ammonium chloride (NH
4Cl) have been grown two-dimensionally on the surface of agar medium. Varying initial concentrations of agar and ammonium chloride in the agar medium, a rich variety of morphologies of dendrites, such as DLA-like structure and dense-branching morphology, were found to be observed. They were classified into five main types according to their pattern characteristics. We report the morphological phase diagram and typical patterns obtained in the present experiments.
View full abstract
-
Osamu Sakai, Yukihiro Shimizu
1992 Volume 61 Issue 7 Pages
2333-2347
Published: July 15, 1992
Released on J-STAGE: June 01, 2007
JOURNAL
RESTRICTED ACCESS
Excitation spectra of the two impurity Anderson model are calculated by using the numerical renormalization group method. The critical transition found by Jones
et al. is examined based on the model that the parity splitting is induced by the f-f transfer matrix,
t. The low energy scale, ω
l⁄
TK, is approximately given as ((
j−
jc)⁄1.5)
2+(
t⁄23
TK)
2, and thus
t suppresses the critical transition, where
j is the exchange coupling normalized by the Kondo temperature
TK,
jc the critical value for the model without
t. The γ-coefficient is proportional to ω
l−1, while the antiferromagnetic susceptibility to lnω
l−1. The phase shift changes continuously near
jc. It tends to singular jump as
t→0. The parity splitting of the single particle excitation spectrum is enhanced by the exchange coupling.
View full abstract
-
Osamu Sakai, Yukihiro Shimizu
1992 Volume 61 Issue 7 Pages
2348-2358
Published: July 15, 1992
Released on J-STAGE: June 01, 2007
JOURNAL
RESTRICTED ACCESS
Excitation spectra of the two impurity Anderson model are calculated for various parameter regions of the f-f transfer,
t, c-f hybridization and the exchange coupling between local spins. The parity dependent potential scattering suppresses the critical transition pointed out by Jones
et al. In the case of small
t, the parity splitting of the f-level is given by
t⁄
Z, where
Z is the enhancement factor of the specific heat in the single impurity problem. In the case of large
t, γ of the electronic specific heat decreases drastically and the parity splitting increases largely. The splitting remains to be order of
t⁄
Z if the induced kinetic exchange coupling is compensated by other mechanism. The fluctuation of the singlet non-uniform superconductivity is relatively large in the electron-hole asymmetric case, but its intensity is about 1/10 of the antiferromagnetic one.
View full abstract
-
Kenji Sumiyama, Hitoshi Amano, Hiroshi Yamauchi, Kenji Suzuki, Takashi ...
1992 Volume 61 Issue 7 Pages
2359-2367
Published: July 15, 1992
Released on J-STAGE: June 01, 2007
JOURNAL
RESTRICTED ACCESS
Amorphous Ce
1−xCu
x alloys (
x=0.09–0.48) have been produced by sputter-deposition. The low-temperature specific heat shows a remarkable enhancement of electronic specific heat coefficient. The magnetic susceptibility can be fitted to a Curie-Weiss law with the effective Bohr magneton number of about 2.5 for
T>50 K and 2 for
T=10–20 K. The electrical resistivity is dominated by the disorder scattering and shows a weak Kondo-type anomaly at low temperatures. These results indicate that the effective electron mass is very heavy even in the random alloy system, where a long-range magnetic order and formation of degenerated Fermi liquid state are suppressed.
View full abstract
-
Daijiro Yoshioka, Hidetoshi Fukuyama
1992 Volume 61 Issue 7 Pages
2368-2381
Published: July 15, 1992
Released on J-STAGE: June 01, 2007
JOURNAL
RESTRICTED ACCESS
Magnetizations of finite two-dimensional systems in external potentials are investigated. Magnetic field and temperature dependence of the magnetization is calculated exactly. It is found that the magnetization is well defined in the limit of vanishing magnetic field as well as in the limit of
T=0, and that it shows large fluctuation at low temperature as the magnetic field is varied. It is shown that this fluctuating magnetization tends to the Landau diamagnetism at higher temperature or by ensemble averaging.
View full abstract
-
Tetsuhiko Tomiki, Tetsuya Kohatsu, Hirofumi Shimabukuro, Yoshiiku Gana ...
1992 Volume 61 Issue 7 Pages
2382-2387
Published: July 15, 1992
Released on J-STAGE: June 01, 2007
JOURNAL
RESTRICTED ACCESS
The absorption spectra due to the 4
f→5
d transitions in Ce
3+ centres have been measured with the use of YAG:Ce
3+ single crystals with a lattice concentration [Ce
3+]
L=(1.28±0.05)%. The data are almost independent of the spectral behaviour of a reference spectrum whose absorption constants are ∼2 cm
−1 at the highest, since the absorption constants of 129 cm
−1 and 50 cm
−1 have been derived, relative to the reference spectrum, at the strongest peaks in the dγ and dε regions, respectively. The absorption area 32.3 cm
−1 eV measured on the strongest dγ-band suggests that about a quarter of the Ce-concentration, [Ce
3+]
M, added in the mixture of the starting powders is incorporated into [Ce
3+]
L as YAG:Ce
3+. It is found that the highest-energy lying dε band is located at 6.06 eV, in agreement with 6.07
0 eV for the corresponding band peak in the excitation spectrum and that the ratio of the absorption area of dγ to that of dε is nearly 2:3.
View full abstract
-
Hiroshi Yamagami, Akira Hasegawa
1992 Volume 61 Issue 7 Pages
2388-2398
Published: July 15, 1992
Released on J-STAGE: May 29, 2007
JOURNAL
RESTRICTED ACCESS
The energy band structure and the Fermi surface are calculated for LaRu
2Si
2 with a body-centered tetragonal crystal structure by a self-consistent relativistic symmetrized APW method with the exchange and correlation potential in the local-density approximation. The main Fermi surface is an extraordinarily large, closed hole sheet with a cross-sectional area exceeding the size of the Brillouin zone itself. There are additionally small hole and electron sheets, all of which have no open orbit. The Fermi surface topology is consistent with the experimental result for the high-field transverse magnetoresistance. By these Fermi surfaces, both the magnitude and the angular dependence of the frequency branches of the de Haas-van Alphen effect measured recently by \={O}nuki
et al. can be explained reasonably well. The Fermi surfaces of the related heavy-electron compound CeRu
2Si
2 and ferromagnetic compound CeRu
2Ge
2 are discussed briefly.
View full abstract
-
Shigenori Tanaka, Noburu Fukushima, Reiko Yoshimura, Tsukasa Tada
1992 Volume 61 Issue 7 Pages
2399-2411
Published: July 15, 1992
Released on J-STAGE: May 29, 2007
JOURNAL
RESTRICTED ACCESS
The electronic structures of layered-perovskite oxides Sr
n+1V
nO
3n+1(
n=1, 2, 3) have been analyzed through ab initio molecular-orbital calculations for VO
6 clusters, using the Hartree-Fock method followed by Møller-Plesset perturbation and configuration-interaction corrections. Comparisons of the electronic states have been made among VO
6, CuO
6 and CuO
4 clusters to study the possibility of realizing vanadate superconductors on the analogy of the high-
Tc cuprate superconductors. Hole- and electron-doped states have also been investigated as well as the undoped state. We thus clarify a number of similarities and differences between the vanadates and the cuprates. It is also suggested that some of these differences may prevent the layered vanadium oxides from becoming high-
Tc superconductors.
View full abstract
-
Makoto Kuwabara, Yoshiyuki Ono, Akira Terai
1992 Volume 61 Issue 7 Pages
2412-2418
Published: July 15, 1992
Released on J-STAGE: May 29, 2007
JOURNAL
RESTRICTED ACCESS
We study velocity damping of a moving soliton in polyacetylene by using numerical simulations within Su, Schrieffer and Heeger’s model. The system is assumed to be at absolute zero of temperature and involves no impurity. In order to get an initial velocity the soliton is accelerated by applying an external electric field. The relaxation time of the soliton velocity has a minimum value when the initial velocity is around the sound velocity of this system. This is a result of the interaction between the moving soliton and the acoustic phonons emitted by the soliton itself. We find that the damping of the soliton velocity is caused by the energy transfer from the moving soliton to the acoustic phonons. The transfer is enhanced when the soliton is surrounded by the acoustic phonons.
View full abstract
-
Misao Murayama, Takashi Nakayama
1992 Volume 61 Issue 7 Pages
2419-2433
Published: July 15, 1992
Released on J-STAGE: June 01, 2007
JOURNAL
RESTRICTED ACCESS
Crystal structures of hetero-crystalline superlattices made of materials with different crystalline structures are proposed and band structures of (hexagonal-diamond Si)/(cubic-diamond Si) and (wurzite ZnS)/(zinc-blend ZnS) superlattices are calculated using the first-principles pseudopotential method within the local-density approximation. It is shown that Si superlattices have indirect band gaps of energy around 1.1 eV, while ZnS superlattices have direct band gaps of energy around 3.8 eV. In both superlattices, the states around the fundamental gap show charge densities localized in one constituent layers, indicating that these superlattices give quantum well systems of good quality. Band offsets are also evaluated.
View full abstract
-
Takashi Nakayama
1992 Volume 61 Issue 7 Pages
2434-2441
Published: July 15, 1992
Released on J-STAGE: May 29, 2007
JOURNAL
RESTRICTED ACCESS
Electronic structures and band offsets of Zinc-compound (001) strained superlattices are calculated by the first-principles pseudopotential method. It is shown that strained superlattices become quantum well systems of good quality for the states around the fundamental gap. With varying the strain surroundings, band offset drastically changes due to the energy-level shift by strain and charge transfer at the interface, mechanism of which is analyzed in order to predict the general feature of the variation of offset in strained superlattices.
View full abstract
-
Akira Saito, Takashi Fujikawa
1992 Volume 61 Issue 7 Pages
2442-2457
Published: July 15, 1992
Released on J-STAGE: June 01, 2007
JOURNAL
RESTRICTED ACCESS
The ARXPS formula derived from the first principles many-body theory is applied to two different adsorbed systems Si(111)-(\sqrt3×\sqrt3)Ga and Sn, to study their Ga 2p and Sn 3d spectra. Special emphasis is placed on the effects of potentials to calculate the scattering phase shifts. Two static potentials are used here; the Watson’s neutral pushed back charge potential and the crystal potential. Beyond the static approximation, we also investigate the optical potential. In the forward scattering the optical potential plays an important role for Ga 2p spectra (365 eV), but it is not so important for Sn 3d spectra (765 eV) because of the high energy scattering. In the large-angle scattering the potentials play a minor role. Other factors such as electron damping, thermal vibration, a finite acceptance angle and charge transfer between adatoms and substrate atoms are also discussed. We find that the first and the third factors play an important role to reduce the anisotropy but the main features are unchanged by these factors. Interlayer distance between the adsorbed Sn layer and the first Si layer is predicted to be 1.8∼2.0 Å from the present ARXPS analyses.
View full abstract
-
Takashi Nakayama
1992 Volume 61 Issue 7 Pages
2458-2468
Published: July 15, 1992
Released on J-STAGE: June 01, 2007
JOURNAL
RESTRICTED ACCESS
Electronic structures of GaP/ZnS and GaAs/ZnSe (001) heterovalent superlattices with different interface configurations are calculated by the first-principles pseudopotential method. As for superlattices with plane interfaces, it is shown that the appearance of interface states makes these systems direct-gap type-II semiconductors and shows large anisotropy in the conductive and optical properties. Moreover large lattice relaxation is expected to occur at the interface. In superlattices with charge-compensated interfaces, an electric field runs along the interface and a quantum well picture is applicable to the states around the fundamental gap. However the calculated band offsets are strongly dependent on the valency of interface atoms, some of which is compared with experiments.
View full abstract
-
Yasuhiro Seguchi, Takefumi Tsuboi, Takao Suzuki
1992 Volume 61 Issue 7 Pages
2469-2476
Published: July 15, 1992
Released on J-STAGE: June 01, 2007
JOURNAL
RESTRICTED ACCESS
The Kogan-Nakagawa (KN) theory is improved to describe a magnetic-field-enhanced superconductivity by incorporating spin paramagnetism and spin orbit scattering. The present theory explains the critical-temperature (
Tc)-enhancement above the zero-field
Tc under parallel magnetic fields observed in layered thin films of Au/Ge except for the exact temperature (
T) dependence of the critical field (
Hc). The conditions for the occurrence of
Tc-enhancement are also discussed as a function of dirtyness. In the vicinity of the critical condition for
Tc-enhancement, the theory yields a three-valued character in
Hc vs
T relation and deviates from the experiment. In contrast to the KN theory, no
Tc-enhancement is expected in the dirty limit because of the spin paramagnetic effect.
View full abstract
-
Nobuyoshi Hosoito, Ko Mibu, Teruya Shinjo, Yasuo Endoh
1992 Volume 61 Issue 7 Pages
2477-2483
Published: July 15, 1992
Released on J-STAGE: May 29, 2007
JOURNAL
RESTRICTED ACCESS
Spin reorientation phenomena in Fe/Nd multilayered films are investigated by neutron diffraction and magnetization measurements. Average magnetic moments of the Fe and Nd layers are estimated at various temperatures in the presence of applied fields. In the field of 9.4 kOe, no spin reorientation is observed in the Fe layer even at 24 K. In contrast, the Nd layer shows the spin reorientation. In weaker fields, the spin reorientation is observed both in the Fe and Nd layers. These facts indicate that the perpendicular anisotropy of the Nd layer is a main origin of the spin reorientation.
View full abstract
-
Adam Lipowski, Masuo Suzuki
1992 Volume 61 Issue 7 Pages
2484-2490
Published: July 15, 1992
Released on J-STAGE: June 01, 2007
JOURNAL
RESTRICTED ACCESS
The coherent-anomaly method proposed by one of the authors (M.S.) combined with a transfer-matrix version of the double-cluster approximation is applied to antiferromagnetic Ising models. We determined both the critical temperature and the critical exponent γ as functions of an external magnetic field. For a square lattice, our results are in a good agreement with the ones obtained recently by the phenomenological renormalization method. For triangle and simple cubic lattices, our results are less definite but still in a qualitative agreement with values predicted by other methods.
View full abstract
-
Kunitomo Hirai
1992 Volume 61 Issue 7 Pages
2491-2502
Published: July 15, 1992
Released on J-STAGE: June 01, 2007
JOURNAL
RESTRICTED ACCESS
The spin density wave in fcc iron is discussed on the basis of electronic structure calculation. The electronic structure of helical spin density wave states with finite local magnetic moments is calculated for fcc iron by a tight-binding model Hamiltonian with a minimal basis set, which is obtained through some simplification to the first-principle LMTO method. The wave vector of the helical spin density wave state of lowest energy is found to be in good agreement with recent neutron diffraction experiments for fcc iron precipitates. The calculation is also carried out for chromium, and difference in characteristics of the spin density wave between fcc iron and chromium is discussed.
View full abstract
-
Kenichi Ishimoto, Masayoshi Ohashi, Hiroshi Yamauchi, Yasuo Yamaguchi
1992 Volume 61 Issue 7 Pages
2503-2511
Published: July 15, 1992
Released on J-STAGE: June 01, 2007
JOURNAL
RESTRICTED ACCESS
Polarized neutron diffraction and magnetic measurement have been carried out on single crystal samples of solid solutions Fe
1−xCo
xSi. The result of magnetic measurement shows that this alloy has a lot of features of itinerant electron ferromagnet i.e. low
TC, small magnetization, large value of μ
C⁄μ
s. The spin density map of Fe
0.6Co
0.4Si is composed of the two kinds of magnetic moments, those are, a 3
d-like moment localized on the (Fe, Co) site (μ
3d) and a weak negative magnetic moment diffused over the crystal (μ
dif). The magnetic moments are estimated to be μ
3d=0.263±0.014μ
B/(Fe, Co) atom and μ
dif=−0.046±0.014μ
B/F.U. These results are discussed with those of typical itinerant electron ferromagnets ZrZn
2, Ni
3Al and MnSi.
View full abstract
-
Hajime Takayama
1992 Volume 61 Issue 7 Pages
2512-2521
Published: July 15, 1992
Released on J-STAGE: June 01, 2007
JOURNAL
RESTRICTED ACCESS
The extended mean field model introduced previously by the present author is reexamined to show that the model can describe a rich variety of phase diagrams caused by competition between the spin glass (SG) order and ordinary linear orders such as the ferromagnetic (FM) one. It is applied to the mean field description of the random network model for SG–FM systems, and qualitative aspects of its phase diagrams are investigated in some detail in comparison with those of the original Sherrington-Kirkpatrick model.
View full abstract