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- Proceedings of the Physico-Mathematical Society of Japan. 3rd Series
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Volume 62, Issue 10
Displaying 1-50 of 51 articles from this issue
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Kazuo Hida1993 Volume 62 Issue 10 Pages 3357-3360
Published: October 15, 1993
Released on J-STAGE: May 29, 2007
JOURNAL RESTRICTED ACCESSThe location of the XY phase in the ground-state phase diagram of the spin-1/2 anisotropic ferromagnetic-antiferromagnetic alternating Heisenberg chain is determined. This model reduces to the spin-1 XXZ chain if the ferromagnetic bond is infinitely strong. The phase boundary between the XY phase and the Haldane phase is determined from the analysis of the numerically obtained energy spectrum of finite-sized systems with the open boundary condition. Our results are consistent with the series-expansion results by Yamanaka et al. within their error bars. The boundary between the ferromagnetic phase and the XY phase is also determined by comparing the energy eigenvalues of these two phases.View full abstractDownload PDF (562K) -
Hironari Miyazawa, Yukio Obata, Hiroshi Suura1993 Volume 62 Issue 10 Pages 3361-3363
Published: October 15, 1993
Released on J-STAGE: May 29, 2007
JOURNAL RESTRICTED ACCESSThe mechanism for producing abundant negative pions by stimulated emission is discussed. The power required to operate such a PASER is proportional to its linear dimension and is such that can be realized in practice. Possible applications to muon-catalyzed fusion are discussed.View full abstractDownload PDF (352K) -
Tadao Kasuya, Masafumi Sera, Takashi Suzuki1993 Volume 62 Issue 10 Pages 3364-3367
Published: October 15, 1993
Released on J-STAGE: May 29, 2007
JOURNAL RESTRICTED ACCESSVarious anomalous properties in CeSb are studied critically. It is shown that they are explained consistently by the formation of a partial magnetic polaron, which disappears with La substitution and is enhanced under pressure, and by a modified Kondo state through an anomalous p-d mixing. However, no Kondo effect is observable at low temperature.View full abstractDownload PDF (624K) -
Hiroshi Kamimura, Yuji Suwa1993 Volume 62 Issue 10 Pages 3368-3371
Published: October 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSA new theoretical explanation is given for the superconducting state in copper oxides. The key feature of the state is the following. A coherent motion of itinerant holes from low-spin to high-spin states in the presence of a relatively long-range antiferromagnetic ordering of the Cu localized spins creates a superconducting state. Based on this state, it is suggested that the attractive interaction between two holes in different energy bands with the same dispersion mediated by Jahn-Teller-type optic phonons is primarily responsible for superconductivity.View full abstractDownload PDF (633K) -
Yuri V. Sushko, Hiroshi Ito, Takehiko Ishiguro, Sachio Horiuchi, Gunji ...1993 Volume 62 Issue 10 Pages 3372-3375
Published: October 15, 1993
Released on J-STAGE: May 29, 2007
JOURNAL RESTRICTED ACCESSApplication of a high magnetic field to the pressure-stabilized superconducting state appearing below Tc1 in κ-(BEDT–TTF)2Cu[N(CN)2]Cl enhances/induces a resistive ground state below Tc2 (<Tc1). The resistivity in the field-induced phase is insensitive to temperature variation. The field-induced transition is also characterized by a marked resistivity versus field hysteresis and by a pronounced long-time dependence.View full abstractDownload PDF (548K) -
Tadao Kasuya, Yoshinori Haga, Takashi Suzuki, Toyotaka Osakabe, Masahu ...1993 Volume 62 Issue 10 Pages 3376-3379
Published: October 15, 1993
Released on J-STAGE: May 29, 2007
JOURNAL RESTRICTED ACCESSThe magnetic orders in CeP under applied magnetic field of up to 70 T are studied based on the layered-type Γ8 magnetic polaron lattice model studied in the previous paper. Entropy changes, total induced moments and results of neutron scattering in various phases are explained consistently. Fermi surface nesting is important to keep the period constant.View full abstractDownload PDF (581K) -
Hideyuki Sato, Yoshihiko Kobayashi, Yuji Aoki, Kazuhiko Shintaku, Nobu ...1993 Volume 62 Issue 10 Pages 3380-3383
Published: October 15, 1993
Released on J-STAGE: May 29, 2007
JOURNAL RESTRICTED ACCESSThe magnetoresistance (MR) at 4.2 K and the temperature dependence of resistivity have been investigated for Au/Fe epitaxial superlattices as a function of Au layer thickness. We found −log (T) temperature dependence of resistivity below about 10 K. The magnitude oscillates as a function of Au layer thickness in phase with the MR oscillation.View full abstractDownload PDF (585K) -
Tetsuya Kato, Toshiya Ishii, Yoshitami Ajiro, Takayuki Asano, Shinji K ...1993 Volume 62 Issue 10 Pages 3384-3387
Published: October 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSNeutron diffraction measurements of single-crystal RbMnBr3 have been performed under magnetic fields applied parallel to the a*-axis of the prototype lattice, where the structural phase transitions are not taken into account. The critical line of a field-induced phase transition, at which the modulation wave number of the spin structure changes, has been obtained in the magnetic phase diagram for 4.2<T<11 K and 0<H<5.0 T, in addition to the in-c-plane spin-flop phase transition.View full abstractDownload PDF (537K) -
Takashi Kambe, Hidekazu Tanaka, Kazukiyo Nagata1993 Volume 62 Issue 10 Pages 3388-3391
Published: October 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSWe investigate the effects of a diagonal interchain interaction J2 on the ESR modes in the ABX3-type antiferromagnets with easy-axis anisotropy.The static properties are described by replacing the conventional interchain interaction J1 by J1−2J2. However, because of the phase difference between the sublattice magnetizations, J2 coupling produces marked effects on some ESR modes in cooperation with J1 coupling. Large separation between the ω1-mode and EPR line for H⊥c and ω2- and ω3-modes for H⁄⁄c (H>HSF) can be derived by maintaining consistency with the canting angle of spins from the c-axis and the spin wave dispersion at zero field. ESR measurements in CsMnI3 are reported. The frequency-field diagram obtained is described well by the model involving J2 coupling.View full abstractDownload PDF (541K) -
Kiyoshi Deguchi, Eiji Nakamura1993 Volume 62 Issue 10 Pages 3392-3394
Published: October 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSThe Rhodes-Wohlfarth ratio μc⁄μp, where μc is the dipole moment determined from the Curie-Weiss constant and μp the saturated dipole moment, was examined for LiTlC4H4O6·H2O (LTT), a displacive ferroelectric having a low Curie temperature of 10 K. The value of μc⁄μp of LTT is obtained to be about 18, which is much larger than those of other ferroelectrics examined previously. This result supports Tokunaga’s prediction that μc⁄μp of displacive ferroelectrics with low Curie temperature exhibit large deviation from unity.View full abstractDownload PDF (335K) -
K\={o}shi Koide, Yutaka Toyozawa1993 Volume 62 Issue 10 Pages 3395-3401
Published: October 15, 1993
Released on J-STAGE: May 29, 2007
JOURNAL RESTRICTED ACCESSA Gedankenexperiment is presented on the effect of imperfect detection of the electron path on the double slit interference pattern. Incorporating into our quantum system the detectors for the electron path and the observer who recognizes the response of the detectors, one can decompose the ensemble of electrons with their spots on the film into three subensembles according as the upper, lower or neither detector responds. Only the third ensemble shows the interference pattern. Negative result measurement is included as a special case. This Gedankenexperiment allows one to put the argument of Bohr’s complementarity of the wave/particle duality on a quantitative basis. The realization of the experiment is well within the high technology of the present day.View full abstractDownload PDF (720K) -
Tohru Koma1993 Volume 62 Issue 10 Pages 3402-3412
Published: October 15, 1993
Released on J-STAGE: May 29, 2007
JOURNAL RESTRICTED ACCESSWe question the validity of the finite-size-correction method based on conformal field theories. It is shown that the method leads to incorrect critical exponents on some of the correlation functions for a one-dimensional free fermion model. The model exhibits the same critical behaviour as in the well-known square-lattice Ising model that is believed to be conformally invariant.View full abstractDownload PDF (1129K) -
Yoichiro Furutani, Koichi Ohashi, Masahiro Shimizu, Atsushi Fukuyama1993 Volume 62 Issue 10 Pages 3413-3424
Published: October 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSThe Thomas-Fermi-Dirac-Weizsäcker statistical model of atoms is applied to a compressed diatomic molecule in a dense plasma. As a two-dimensional problem, we analyze numerically a spatial profile of the screening function and the electron density inside a closed boundary surface. We also calculate the Helmholtz’s excess free energy as a function of the internuclear distance, to examine a possibility of the binding state.View full abstractDownload PDF (1177K) -
Hidetoshi Suemitsu, Hideki Kitaura, Katsushi Seki1993 Volume 62 Issue 10 Pages 3425-3431
Published: October 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSThe relative production rates of Cs2+ ions produced through two-photon ionization of cesium dimers Cs2 were measured in the wavelength range 620–670 nm. The calculated production rates of Cs2+ ions produced via the intermediate state C 1Πu from X 1Σg+ agreed fairly well with the experimental results. The production rates via the intermediate state 1Σu+, which is close to C 1Πu, were calculated. The calculated results, however, showed the completely different function of wavelength from that of the experimental results. Thus we concluded that Cs2+ ions are mainly produced by the processes via the intermediate state C 1Πu. It was made clear that most of the cesium dimers Cs2 excited in the super excited states Cs2** by absorption of two photons are autoionized to produce Cs2+ ions.View full abstractDownload PDF (784K) -
T. P. Pandya, L. M. Bali, P. Jha, A. Srivastava, R. K. Shukla, V. Saxe ...1993 Volume 62 Issue 10 Pages 3432-3440
Published: October 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSSpontaneous and coherent emission of radiation in a FEL with planar wiggler and axial magnetic fields is investigated. The eccentricities of the resulting electron trajectory and spontaneous emission are seen to be different. On interaction with e.m. radiation electron orbits give rise to elliptically polarised coherent emission at principal and harmonic frequencies. Beam amplifications at higher harmonics peak at lower axial field strengths. The peak gains are significantly larger than the gain obtained at the next lower frequency in the absence of axial magnetic fields.View full abstractDownload PDF (904K) -
Yong Kweon Suh1993 Volume 62 Issue 10 Pages 3441-3445
Published: October 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSMotion of a point vortex in a 90°-corner which is subject to a potential flow is studied. There exists a fixed point at which the vortex is stationary. It turns out that the vortex motion is periodic regardless of the initial position except the fixed point. The fixed point is apart from the corner in a distance proportional to the square root of the ratio of the vortex strength (circulation) and the strength of the potential flow. The period of the circulatory motion of the vortex in a small vicinity of the fixed point is in inverse proportion to the potential-flow strength and is independent of the vortex strength. The motion of the fluid driven by both the potential flow and the vortex is also studied; depending on the location of the stagnation points, generally four kinds of flow patterns are classified.View full abstractDownload PDF (507K) -
Isao Katanuma, Yasuhito Kiwamoto, Nobuyoshi Ohyabu, Kameo Ishii, Kiyos ...1993 Volume 62 Issue 10 Pages 3446-3459
Published: October 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSThe electron distribution function is derived analytically with the linearized Fokker-Planck equation in order to analyze the electron confining potential in the geometry of mirror ratio R<<1. The magnitude of the potential is determined by the electron axial loss time (transit time) τ⁄⁄ when τ⁄⁄ is longer than the coulomb collision time τ, on the other hand the magnitude of the potential depends mainly on τ when τ⁄⁄\lesssimτ. Especially, it is found that the electron confining potential does not depend on the emission rate γ of electrons hitting the wall as long as τ⁄⁄<<τ.
The bounce-averaged nonlinear Fokker-Planck simulation is carried out in order to investigate the electron confining potential in the case of R=1. The electron temperature ratio Te⊥⁄Te⁄⁄ depends strongly on the ratio τ⁄τ⁄⁄. The magnitude of the potential obtained in the simulation has a tendency to decreasing with the ratio τ⁄τ⁄⁄.View full abstractDownload PDF (1359K) -
Mitsuhiro Nambu1993 Volume 62 Issue 10 Pages 3460-3475
Published: October 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSThe plasma-maser process including electrostatic waves propagating obliquely to an external magnetic field is studied. It is shown that the results based on the linear response theory agree with the previous standard results obtained by M. Porkolab and R. P. H. Chang (Phys. Fluids 15 (1972) 283). It is found that the polarization term for a magnetized plasma gives a finite contribution to the plasma maser in contrast to the case of an unmagnetized plasma, and that the results for the magnetized plasma reduce to those for the unmagnetized plasma in the limit of zero magnetic field. There does not exist discontinuous jump between the expressions for the unmagnetized and magnetized plasmas.View full abstractDownload PDF (1428K) -
Kazuyuki Ohe, Shigeki Hayashi, Takashi Kimura1993 Volume 62 Issue 10 Pages 3476-3485
Published: October 15, 1993
Released on J-STAGE: May 29, 2007
JOURNAL RESTRICTED ACCESSTwo ionization wave modes simultaneously excited in a low discharge current He positive column are detected by an auto-regression method. One dominant mode which slightly damps can be predicted by the dispersion relation calculated under the assumption that a group of electrons are resonant with a peculiar wave characteristic voltage. The dispersion relation obtained experimentally for the other evanescent mode agrees well with the theoretical dispersion calculated from the hydrodynamic equations using the two-electron temperature approximation.View full abstractDownload PDF (992K) -
Masayoshi Taguchi1993 Volume 62 Issue 10 Pages 3486-3491
Published: October 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSA poloidally varying electrostatic potential due to a plasma heating anisotropic in velocity space is investigated in the collisionless regime for an axisymmetric plasma. Based on a linearized drift kinetic equation in a presence of external energy-source term, an analytic expression for this electrostatic potential is derived by means of an eigenfunction technique and a variational method. By using this analytic expression, the enhancement of the neoclassical transport coefficients by the anisotropic heating is discussed.View full abstractDownload PDF (567K) -
G. Gnudi, Tsuguhiro Watanabe1993 Volume 62 Issue 10 Pages 3492-3505
Published: October 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSA new method for integrating differential equations is presented. The method is explicitly described until the order 14, and it has been proven to be A-stable and symplectic with respect to linear Hamiltonian systems.View full abstractDownload PDF (1071K) -
Ryo Maruta, Atsuya Makita, Ken-ichi Ohshima1993 Volume 62 Issue 10 Pages 3506-3512
Published: October 15, 1993
Released on J-STAGE: May 29, 2007
JOURNAL RESTRICTED ACCESSX-ray measurements have been performed on the structure of layered compound Cu0.15Ti1.08S2 at room temperature. Weak diffuse scatterings at (1/2, 0, 3/2), (1/2, 1/2, 3/2) and (1, 1/2, 3/2) in reciprocal space are observed. This reveals that both the intercalated copper atoms and self-intercalated titanium atoms are three-dimensionally correlated with each other and the stacking sequence αβαβ… is deduced. By analyzing diffuse intensity, the short-range order (SRO) parameters were determined. A 2×2 in-plane ordered structure is expected for the low temperature phase. The estimated in-plane and interlayer correlation lengths are about 12 A.View full abstractDownload PDF (644K) -
Takashi Sakuma, Fumihito Suzuki, Shoji Saitoh, Kazumasa Sugiyama, Eiic ...1993 Volume 62 Issue 10 Pages 3513-3518
Published: October 15, 1993
Released on J-STAGE: May 29, 2007
JOURNAL RESTRICTED ACCESSThe diffuse background intensity of α-Cu2Se was observed by the anomalous X-ray scattering (AXS) measurement at the Cu K-absorption edge using synchrotron radiation. The theoretical treatment including the effects of the correlation between the thermal displacements of atoms was applied to the analysis of the observed diffuse background of α-Cu2Se. The structural model for α-Cu2Se formerly reported by the present authors has been confirmed by the analysis of the diffuse background.View full abstractDownload PDF (535K) -
Yoshiyuki Matsumoto, Kiyoshi Ogura1993 Volume 62 Issue 10 Pages 3519-3526
Published: October 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSThe Slater and the Takagi models of the ferroelectric phase transition in KH2PO4 (KDP) have been extended to the model that the number of each proton configuration depends on time. We adopt the two proton configurations proposed by Silsbee et al. besides the Slater’s and the Takagi’s configurations. The dynamical susceptibility, χ(ω), is obtained in the form of the sum of two Debye-type functions, where we have gained two relaxation times with different temperature dependence. One of them, τ− tends to infinity when temperature approaches the transition point from the paraelectric region. This feature is very similar to the results of Yoshimitsu et al. Next, we determine the three orientation energies, ε0, ε1 and ε2, using some experimental results and then calculate two relaxation times numerically. The polarization relaxation mode is found in the narrow frequency region within 0∼0.5 cm−1.View full abstractDownload PDF (690K) -
Tomoyuki Hikita, Yoshiko Tezuka1993 Volume 62 Issue 10 Pages 3527-3531
Published: October 15, 1993
Released on J-STAGE: May 29, 2007
JOURNAL RESTRICTED ACCESSUltrasonic velocity and attenuation were measured on TSCC single crystals at 10 MHz. The longitudinal sound was propagated along the a, b and c axes. The velocity was measured by pulse-echo-overlap-method. The sound velocities along the a and c axis show a sharp drop at Tc, whereas the attenuation coefficients a sharp peak (width of less than 0.1 K) at the same temperature. These anomalies can be analyzed by Landau-Khalatonikov process. The longitudinal sound propagated along the ferroelectric b axis also shows anomalies in velocity and attenuation. However the width of the peak of the attenuation is about 1.3 K and is much wider than those of perpendicular ones. The anomalies in this direction were interpreted in terms of the peculiar nature of this ferroelectric where the short range interaction is playing important role for the phase transition.View full abstractDownload PDF (690K) -
Yoji Ohashi, Masashige Matsumoto1993 Volume 62 Issue 10 Pages 3532-3538
Published: October 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSThe band motion of muons in superconductors is studied in detail. Both the damping rate and the effective mass of the muon due to the interaction with conduction electrons are examined. Then, the average hopping rate of a muon is obtained by combining these quantities. The results are compared with that obtained by the double-well model and the relation between the two is discussed. In addition, as an extention of our theory, the quantum diffusion in some unconventional superconductors is also examined.View full abstractDownload PDF (715K) -
Takafumi Kita1993 Volume 62 Issue 10 Pages 3539-3556
Published: October 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSBroken time-reversal (T) symmetry of anisotropic superfluidity implies topological change of the whole Fermi sphere. An infinite string pierces through the Fermi sphere; the phase of the pair state |k, −k⟩s is multivalued around it; and at T=0, the one-particle occupation number n(s)(k) vanishes on the string. Through these observations, this paper settles the problem of the intrinsic orbital angular momentum in 3He–A: The momentum density at T=0 is given by g=NsMvs+(1⁄4)∇×(Nshl)−(h⁄2)C0l(l·∇×l) with C0=0, namely, the third term is absent due to n(s)(k)=0 for k⁄⁄l. The process reveals that the Green’s function approach based on the plane wave expansion fails to describe the topological change. Also, the conclusion raises several basic problems such as the divergence of Hc2 for T-breaking superconductivity. Finally, this paper presents a principle connecting the magnetic field with the phase singularity of the wave function. Its implications to the charged-anyon model and the Dirac monopole are also discussed.View full abstractDownload PDF (2168K) -
Shintaro Mori, Miki Wadati1993 Volume 62 Issue 10 Pages 3557-3564
Published: October 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSIn the studies of the curvature instability, the phase separation of the intercalated particles in the membrane and the amphiphilic molecules has been assumed. In the present paper, we discuss another mechanism; we consider the case where the intercalated particles move diffusively except for the coupling with the curvature of the membrane. The instability conditions are explicitly shown for flat and spherical cases. Based on the results, we give an intuitive explanation to the reversible echinocytosis of the red blood cell. We also discuss the application to the multi-component microemulsion systems.View full abstractDownload PDF (732K) -
Shintaro Mori, Miki Wadati1993 Volume 62 Issue 10 Pages 3565-3574
Published: October 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSWe discuss the condition for the curvature instability in d-dimensional surface. We give necessary and sufficient conditions for the instability in the cases where the order parameters on the membrane are described by the φ4-theory and the spherical model. In the spherical model case, applying Large D expansion (where D is the dimension of the bulk space in which the membrane is embedded), we obtain the phase diagram of this system.View full abstractDownload PDF (884K) -
Susumu Ogawa, Shigemasa Suga, A. E. Bocquet, Fumitoshi Iga, Mitsuo Kas ...1993 Volume 62 Issue 10 Pages 3575-3589
Published: October 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSWe report on X-ray photoemission (XPS), Bremsstrahlung isochromat (BIS) and 4f resonant ultraviolet photoemission (4f RPES or UPS) spectroscopy of Ce(Pd1−xCux)3 (0≤x≤0.133). With increasing x, the 4f1 BIS peak clearly observable in CePd3 is strongly depressed, the 4f2 BIS peak is found to shift to lower energies and the intensity of the 3d94f0 component of the Ce 3d core XPS is found to become weaker. These experimental results are discussed in comparison with the spectra calculated by using the impurity Anderson model. It is found that lowering of the 4f level energy εf along with reduction of the 4f hybridization strength V with x can qualitatively reproduce the experimental result. It is also strongly suggested that the 4f-4f Coulomb energies are different for the 4f BIS and 3d XPS final states.View full abstractDownload PDF (1748K) -
Kazuo Soda, Tamiko Mori, Hideaki Kitazawa, Masayuki Hagiwara, Koichi K ...1993 Volume 62 Issue 10 Pages 3590-3597
Published: October 15, 1993
Released on J-STAGE: May 29, 2007
JOURNAL RESTRICTED ACCESSWe have measured the valence-band photoelectron spectra of (La1−xSrx)2CuO4−δ single crystals. Spectra obtained at low temperatures (30–80 K) are similar to each other as well as the results reported so far: The intensity at the Fermi level is quite low and the valence-band maximum is shifted to higher binding-energy than what the energy-band calculation predicts. At room temperature the intensity of the 3 eV band is reduced rapidly while the specimen is kept in dark, while it shows a quick recovery when the specimen is exposed to the excitation light for photoelectron measurements. This suggests that a photo-assisted process may take part in this phenomenon. Some possible mechanisms for the photo-induced changes are discussed.View full abstractDownload PDF (1135K) -
Yoshiki Hori, Keita Kishigi, Kazushige Machida1993 Volume 62 Issue 10 Pages 3598-3608
Published: October 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSThe charge or spin density wave (DW) formation in one-dimensional (1D) electron systems under an external incommensurate potential is shown to be characterized by infinitely many order parameters (MOP) and infinitely many mean-field solutions with almost degenerate energies. We investigate various properties of such a DW state, including the band structure and the relative magnitude of the OP’s as functions of the strength and period of the external potential. The complexity of the configuration space of the mean-field solutions is described by ultrametricity. The observed field-induced SDW transition of 2D systems such as (TMTSF)2X is discussed where the magnetic field plays a role of the incommensurate potential in this context.View full abstractDownload PDF (1514K) -
Y.-R. Jang, B. I. Min1993 Volume 62 Issue 10 Pages 3609-3614
Published: October 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSThe quasi-particle spectral weight at the Fermi level (ZF) in the two-dimensional (2D) electron gas is determined as a function of density. A model local field correction factor (G(q)) possessing the correct features both in the small and large q limits is introduced and used to calculate the ZF, by evaluating the electron self-energy within the GW approximation. It is found that the ZF calculated using the present G(q) is smaller than the one calculated using the Hubbard G(q) implying that the correlation interaction makes the system more localized. Our result also indicates that high Tc superconductors, if described by a 2D electron gas system, will exhibit a small but nonzero (∼0.2) quasi-particle spectral weight at the Fermi level.View full abstractDownload PDF (771K) -
Role of the Valence Band Density of States in the Piezoresistance of p-Type Semiconductors Si and GeYamichi Ohmura1993 Volume 62 Issue 10 Pages 3615-3620
Published: October 15, 1993
Released on J-STAGE: May 29, 2007
JOURNAL RESTRICTED ACCESSIt has been shown that unusual hole concentration changes in p-type Si and Ge under stress reported in the earlier work are well accounted for in terms of density of states (DOS) change of each hole due to stress. The DOS of heavy-hole band decreases, while that of light-hole band increases near the band edge region for both tensile and compressive stresses, which impedes the carrier transfer and hence results in extremely small, nearly stress-quadratic hole concentration changes. It has also been demonstrated that, when these DOS changes overwhelm the carrier transfer effect, even the decrease of the low-energy heavy hole concentration takes place at low temperatures.View full abstractDownload PDF (764K) -
Hiroshi Kaneko, Takehiko Ishiguro, Jun Tsukamoto, Akio Takahashi1993 Volume 62 Issue 10 Pages 3621-3632
Published: October 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSHighly conductive heavily iodine-doped polyacetylene changes from metallic to nonmetallic by room-temperature aging. For this change, thermoelectric power varies little, suggesting that the transition is not ascribed to change in carrier concentration but to increase of the degrees of disorder. Corresponding to the transition, low temperature magnetoresistance changes from negative to positive on crossing the transition. The magnetoresistance in the metallic region is interpreted in terms of weak localization, while that in the nonmetallic state is explained by field effect to variable range hopping conduction among Anderson localization states. The transition to the nonmetallic state proceeds inhomogeneously.View full abstractDownload PDF (1468K) -
Tsuyoshi Ueta1993 Volume 62 Issue 10 Pages 3633-3638
Published: October 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSBehavior of an electron beam injected from a waveguide into an open space in magnetic fields is studied by the method analogous to that Kirchhoff applied to the diffraction of light. It is found that magnetic field quantum-mechanically collimates electron beams. An electron beam injected from an orifice travels longer distance than that classical theory predicts before reflection on the boundary. Substructure of electron beams around the reflection point is interpreted by introducing the effect of magnetic fields to the diffraction theory in the absence of a magnetic field.View full abstractDownload PDF (727K) -
Ken-ichi Oshio, Hideo Yahata1993 Volume 62 Issue 10 Pages 3639-3650
Published: October 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSA one-dimensional model system of the Gunn-effect device is considered. It consists of an n+-n-n+ GaAs sandwich structure where the high-n+ contact layers on both ends are linearly graded to the uniformly distributed low-n bulk region and a half-wave sinusoidal doping notch is incorporated near the cathode. Using the finite differece method, spatio-temporal evolution of the system subject to the dc and the rf-alternating fields is computed with the amplitudes and the frequency being taken as the control parameters. Current oscillations associated with the cyclic traveling high-electric-field domain are shown to materialize over a range of the control parameters. In particular, the current oscillations become chaotic at specially chosen values of these bias parameters.View full abstractDownload PDF (1426K) -
Tsuyoshi Yamaguchi1993 Volume 62 Issue 10 Pages 3651-3660
Published: October 15, 1993
Released on J-STAGE: May 29, 2007
JOURNAL RESTRICTED ACCESSElectronic states are calculated by the DV–Xα–LCAO method for two model clusters C60Si57H44 and C60Si41H36 of the C60/Si(001) surface, where the C60 molecule resides on four and two Si dimers, respectively. Due to the electron transfer from the Si surface, the C60 molecule of the former (latter) cluster has ionicity −2.44 (−1.96). The highest occupied molecular orbital (HOMO) of the C60 molecule of the former cluster is lower than that of the latter cluster. This implies that the C60 molecule of the former cluster is more stable than that of the latter cluster. For both clusters, occupied (unoccupied) orbitals of the C60 molecule near the HOMO have high charge density around double bonds between two hexagons (around single bonds on pentagons). The charge density of an orbital has 4 or more stripes which should be compared with the scanning tunneling microscopy images.View full abstractDownload PDF (1293K) -
Koichi Ichimura, Kazushige Nomura1993 Volume 62 Issue 10 Pages 3661-3679
Published: October 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSThe electron tunneling study was carried out on Bi2Sr2CaCu2O8 with use of the scanning tunneling microscope. Both the cleaved and lateral surface of single crystal were investigated. The electronic density of states for the superconducting phase was correctly obtained at the lateral surface. It shows the finite gap on the whole Fermi surface clearly, while the gap has a considerable anisotropy. The temperature dependence of the magnetic field penetration depth was also measured and its thermally activated behavior confirmed the finite gap again. These results indicate the large s-wave component in the pair wave function and the fair contribution of d-wave as well. The attractive force between electrons is not only due to the on-site interaction, but also the extended one.View full abstractDownload PDF (2583K) -
Manabu Ikebe, Yoshihisa Obi, Hiroyuki Fujishiro, Hiroyasu Fujimori1993 Volume 62 Issue 10 Pages 3680-3685
Published: October 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSThe dimensional crossover from anisotropic three-dimensional to two-dimensional behavior in the temperature dependence of the parallel critical field has been studied for Nb/Al2O3 superconductive multilayers as a function of the structural modulation wavelength λ. The thicknesses of the superconductive Nb sublayer (d Nb) and the Al2O3 tunneling barrier sublayer (d Al2O3) were varied up to 100 Å. In accord with the calculation due to Deutscher and Entin-Wohlman, the crossover occurs in the vicinity of T*, where the perpendicular coherence length ξ⊥(T) satisfies the relation, 1.4ξ⊥(T*)=λ, irrespective of the ratio λ⁄d Nb.View full abstractDownload PDF (685K) -
Fumihisa Suzuki, Chikara Ishii1993 Volume 62 Issue 10 Pages 3686-3693
Published: October 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSThe thermodynamic properties of quasi-two-dimensional Heisenberg antiferromagnet have been investigated in the framework of the modified spin-wave theory. A set of self-consistent equations is derived for chemical potential μ and two mean-field parameters, characterizing the nearest-neighbor spin correlations. Solving these equations under the condition μ=0, we derive a formula determining the Néel temperature TN as a function of the coupling ratio ε≡J⊥⁄J⁄⁄ between the interplane and intraplane exchange couplings. In the region above TN, the self-consistent equations have been solved numerically, to discuss the temperature dependence of the correlation length.View full abstractDownload PDF (888K) -
Isao Harada, Mutsuko Fujikawa, Isao Mannari1993 Volume 62 Issue 10 Pages 3694-3701
Published: October 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSGround-state phase diagram and low-lying excitation spectrum of the one-dimensional S=1 anisotropic Heisenberg antiferromagnetic chain with nearest neighbor and next nearest neighbor interactions are studied by means of an approximate mapping of the original S=1 spin Hamiltonian to the effective fermion Hamiltonian, which describes the dynamics of spin zero defects in antiferromagnetic environments (domain walls in the Néel state). We find that the frustration due to the next nearest neighbor interactions works cooperatively with quantum fluctuation in the Haldane state and stabilizes it. This is naturally explained in terms of the spin zero defect. In addition, we discuss characteristic features of the excitation spectrum in connection with its ground-state properties.View full abstractDownload PDF (899K) -
Yoji Ohashi1993 Volume 62 Issue 10 Pages 3702-3709
Published: October 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSThe uniform susceptibility of high-Tc cuprates is studied by focusing on its anomalous temperature dependence. Our result shows that the uniform susceptibility has a temperature dependence due to the coupling with antiferromagnetic (AF) spin fluctuations. Furthermore, the difference of the temperature dependence between the lightly doped region and the overdoped region is explained with this mechanism as related to the strength of the AF spin fluctuations.View full abstractDownload PDF (983K) -
Tadashi Shimizu, Haruyoshi Aoki, Hiroshi Yasuoka, Toshinobu Tsuda, Yut ...1993 Volume 62 Issue 10 Pages 3710-3720
Published: October 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSThe tensor components of the magnetic susceptibility (χ) and the Knight shift (K) at the plane Cu(2) sites have been precisely measured in YBa2Cu3Ox with x=6.98, 6.48 and 6.0. Using the temperature dependent χ and K observed in YBa2Cu3O6.48, we have carried out the analysis of K-χ diagram to make a separation of the observed susceptibility into orbital and spin contributions. Assuming the orbital contribution from the Cu(2) ions is independent of x for 6.0≤x≤7.0, we have obtained the x dependent spin susceptibility of the Cu(2) ions. The obtained spin susceptibility is discussed in comparison with the theoretical predictions of the Heisenberg model, the Stoner model and a band structure calculation. A complete set of the parameter values used in the crystal field model of a Cu2+ ion (the crystal field splittings, the orbital reduction factor, the spin-orbit coupling and the g-factors) has been determined from the K-χ analysis.View full abstractDownload PDF (1425K) -
Takeo Jo, Shin Imada1993 Volume 62 Issue 10 Pages 3721-3727
Published: October 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSWe give an interpretation for the observed systematic trend of magnetic circular dichroism (MCD) in L2,3 photoabsorption of rare-earth (RE) atoms from Ce to Tm in ferro- or ferrimagnetic RE2Co17 assuming the 2p→5d electric dipole transition. We assume that the 4f state of trivalent RE ions is in the polarized Hund-ground-state. We then take into account the spin and orbital magnetic moments induced in the RE 5d state through the intraatomic 4f-5d exchange interaction approximated by a molecular field with assuming a band width of several eV and one tenth filling of the 5d band. The integrated MCD intensity calculated with a naive one-electron picture is shown to correspond well to the observed trend. The 5d orbital moment estimated both from the present model and from a MCD sum rule applied to the experiment is of the order of ∼0.1 μB, which is comparable to the 5d spin moment.View full abstractDownload PDF (962K) -
Nobuyuki Katoh, Masatoshi Imada1993 Volume 62 Issue 10 Pages 3728-3740
Published: October 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSThe ground state energy, the energy gap and the Fourier transform of the staggered spin correlation function S(Q) at zero temperature are investigated for the S=1⁄2 antiferromagnetic Heisenberg model on a dimerized square lattice with the help of the spin-wave approximations, the second-order perturbation expansion and the quantum Monte Carlo simulations. In contrast to one-dimensional case, the spin gap appears above a finite critical value of the dimerization parameter. δc\simeq0.303, where the second-order transition takes place. The antiferromagnetic long range order exists below δc. The critical exponent of the order parameter in the antiferromagnetically ordered state is estimated by quantum Monte Carlo calculation to be \simeq(δc−δ)β with β=0.27±0.04, while the correlation length in the spin gap region is scaled as \simeq(δ−δc)−ν with ν=1.36±0.05. All of them are different from the estimates in one-dimension, ν=1 and the spin-wave approximation, β=ν=1. Possible relevance of our result for the spin gap behavior in high-Tc superconductors is also discussed.View full abstractDownload PDF (1581K) -
Fumio Maruyama, Hiroyuki Nagai, Kengo Adachi1993 Volume 62 Issue 10 Pages 3741-3750
Published: October 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSThe magnetic properties of Y2(Co1−xTx)14B (T=Mn, Fe, Ni) are studied by means of NMR and magnetic measurements. The substitution of Fe and Mn for Co in Y2Co14B affects the magnetic anisotropy with a spin reorientation from plane to axis. The relationships between the anisotropy changes and the hyperfine fields of 59Co nuclei determined by NMR are studied. The evaluated Co orbital moments and the increases of the hyperfine fields at 8j1 and 8j2 sites are larger than those at other sites, so Co at 8j1 and 8j2 sites give the large contribution to the anisotropy of the 3d sublatice. These anisotropy changes are interpretted by the estimated local anisotropy energy per atom, ES, at each site and the preferential substitution of Fe and Mn for Co at 8j2 site.View full abstractDownload PDF (1078K) -
Mitsumasa Ishiwata1993 Volume 62 Issue 10 Pages 3751-3761
Published: October 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSSelective spin inversion usually produces transfer of the longitudinal magnetization in a coupled spin system. Under irradiation of a stirring-field, however, transverse ones and multiple quantum coherences can also be simultaneously transferred in this process. For a coupled 13C–1H spin system under irradiation resonant with one of the 1H lines, 13C tickling spectra are observed immediately after inversion of one component of the 13C-polarizations. Spectra thus obtained are considerably different from a simple selectively-inverted pattern of the steady-state ones. These changes depend on amplitude and frequency of the rf field, frequency and phase of the inversion pulse and inhomogeneity of the static magnetic field. The most prominent change in these spectra can be explained by transfer of zero quantum coherence, which is made in the differential form into each line of the spectra.View full abstractDownload PDF (1184K) -
Hiroharu Yorikawa, Masato Itenishi, Shinji Muramatsu1993 Volume 62 Issue 10 Pages 3762-3763
Published: October 15, 1993
Released on J-STAGE: May 29, 2007
JOURNAL RESTRICTED ACCESSDownload PDF (255K) -
Yoshinori Tsuchiya, Hideyuki Takita, Shigeyuki Murayama, Yoshikazu Ham ...1993 Volume 62 Issue 10 Pages 3764-3765
Published: October 15, 1993
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSDownload PDF (313K)