Numerical evidence that the number of pure states in the spin glass phase is infinite near the ferromagnetic phase boundary for the three dimensional (3D) ± J Ising model and 3D gauge glass models is presented. It is consistent with the mean field theory which suggests the multivalley structure of the spin glass phase. We will show that the onset of the ferromagnetic long-range order and that of the ferromagnetic spontaneous symmetry breaking do not coincide with each other, and this phenomenon characterizes the structure of the phase space.

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The orbital ordering in the ferromagnetic YTiO₃ (T_C ∼= 30 K) has been observed by means of the polarized neutron diffraction technique. The observed magnetic form factors obtained from the aspherical contribution of the spin density distribution have been satisfactorily explained by the linear combination of the wave functions |zy› and |zx› in terms of the orbital ordering scheme.

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Jahn-Teller structural phase transitions are examined using a simple Ginzburg-Landau approach. The order parameter representing orbital order is complex for the case of doubly degenerate d-orbital states. We find tricritical behavior in ferromagnet-like orbital order under applied uniaxial stress and in antiferromagnet-like orbital order with varying the strength of the interaction between the two sublattices.

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Sound propagation in a Fermi liquid with impurities is studied using the Landau-Boltzmann equation and the result is compared with that of a recent experiment in liquid ³He in aerogel by the Northwestern University group. The sound absorption calculated using a fixed impurity model is a few orders of magnitude larger than the experimental value. We take into account the simultaneous motion of aerogel molecules and propose a model in which the momentum loss of ³He quasi-particles during collisions with the aerogel is converted to a drag force that acts on the aerogel molecules. This collision drag model provides a reasonable description for the temperature and the pressure dependence of the observed sound velocity and absorption.

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Transitions from a paired quantum Hall state to another quantum Hall state in bilayer systems are discussed in the framework of the edge theory. Starting from the edge theory for the Haldane-Rezayi state, it is shown that the charging effect of a bilayer system which breaks the SU(2) symmetry of the pseudospin shifts the central charge and the conformal dimensions of the fermionic fields which describe the pseudospin sector in the edge theory. This corresponds to the transition from the Haldane-Rezayi state to Halperin's 331 state, or from a singlet d-wave to a triplet p-wave ABM type paired state in the composite fermion picture. Considering interlayer tunneling, the tunneling rate-capacitance phase diagram for the ν=5/2 paired bilayer system is discussed.

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We compare the scattering dynamics of H₂/Cu₃Pt(111)[121] and H₂/NiAl(110)[110], with the corresponding results for H₂/Cu(001)[100] and H₂/Ni(110)[001]. We show that H₂ can indeed distinguish between surfaces and between surface components, and these discernible (by H₂) differences manifest as measurable/observable transitions in the internal states of the scattered H₂. Based on these results, we discuss how, after a systematic and comprehensive study, it would be feasible to study adsorbate-surface interaction (local surface reactivity), and surface structures, as well as to determine the corresponding effective potential energy (hyper-) surface using H₂(D₂) probes.

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Little-Parks oscillation of a Möbius strip (or ring, equivalently) made of a superconductor is studied based on Ginzburg-Landau theory. It is shown that, if the strip is sufficiently wide, a novel state appears when the number of magnetic flux quanta threading the ring is close to a half odd integer. As a result, the shape of Little-Parks oscillation of critical temperature is modified. We estimate the free energy of this state and give the phase diagram of the superconducting Möbius strip in a magnetic field.

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The superconductivity of the two-dimensional d-p model up to the second order of the Coulomb repulsion U_d is investigated in the weak-coupling formalism. Near the half-filling, the superconducting gap function has b_1g symmetry. The dependences of the gap magnitude on both the total hole density and the ratio of the number of d-holes to the number of p-holes are also studied. These dependences make it clear that the presence of the Van Hove singularity can make gap magnitudes large even in the case of small U_d.

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The Cu-NQR spectra were measured in a wide temperature range from 300 K to 1.5 K to investigate the ordering process and the structure of the static spin-charge stripe order in La_2-x-yEu_ySr_xCuO₄ with x=1/8. The usual NQR spectrum observed above the structural transition temperature, T_d2=138 K, from LTO to LTT shows the decrease of the signal intensity below T_d2 due to the rapid increase of the spin echo decay without change of the lineshape, and the signal wiped out completely below 40 K. We assigned the temperature T_charge∼=85 K, at which the spin echo decay rate increases abruptly, as a representative one for the slowing down toward static charge stripe ordering. Below T_spin ∼= 8 K, the signal starts to reappear as an abnormally broad spectrum with a tail extending to 70 MHz or more, which is evidence of the static spin and/or charge order. The spectrum is simulated satisfactorily in terms of the stripe order with the modulation amplitude for the Cu moment of about 0.22 μ_B.

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A two-route traffic model with a built-in decision-making process is proposed and studied numerically. The instantaneous average speeds on the routes are announced as global information. Two types of drivers, dynamic and static, are introduced. The dynamic drivers use the global information for making decisions. It is shown that announcing the instantaneous average speeds on the routes results in a better performance of the two-route system in terms of the traffic flux compared to announcing the transit time. When the static drivers randomly select a route, the presence of the dynamic drivers does not improve the traffic flux of the system. When the static drivers tend to select a particular route, the presence of dynamic drivers leads to a higher flux. Our model thus incorporates the effects of adaptability into the cellular automaton models of traffic flow.

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Several species of tilings with eight-fold symmetry generated by means of inflation rules are studied. They can also be obtained by superposition of other patterns. The complexity of the structures is reflected in the sets of vertex configurations. Composition of the basic inflation rules gives face to face tilings. The diffraction patterns of the simple tilings show Bragg peaks.

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We propose a method to characterize discrete time evolution equations, which generalize discrete time soliton equations, including the q-difference Painlevé IV equations discussed recently [K. Kajiwara et al.: nlin. SI/0012063; T. Masuda: nlin. SI/0107050].

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By making use of a naïve model of nonlinear dielectric medium, the propagation of electromagnetic waves with long wave length is investigated. By the reductive perturbation method, the equation governing it has been derived, which takes the form of a vector type of modified KdV equation. Based upon this equation, we have considered the behaviors of nonlinear waves. It is found that this equation has a vector type of dark solitary wave solution in addition to a scalar type of bright or dark solitary wave solutions. The weak modulation of the wave train solution is described by the coupled nonlinear Schrödinger equation and shows the nonlinear rotation of the principal axes of the elliptically polarized wave.

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We study dynamics of a wavefunction for the nonlinear Schrödinger equation with attractive self-interaction under a harmonic potential. By use of the variance identity and a rigorous inequality, we obtain a sufficient condition for the collapse of the wavefunction. By applying this method, we investigate the dynamic stability of a trapped Bose-Einstein condensate and its dependence on the initial shape of the condensate. The result agrees qualitatively well with the results of the time-dependent variational method. We find that the anisotropy introduced in the initial state has a significant effect on the stabilization.

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We study a correlation function for the one-dimensional isotropic XY model (XX0 model), which is called the Emptiness Formation Probability (EFP). It is the probability of the formation of a ferromagnetic string in the anti-ferromagnetic ground state. Using the expression of the EFP as a Toeplitz determinant, we discuss its asymptotic behaviors. We also compare the analytical results with numerical calculations as the density-matrix renormalization group and the quantum Monte-Carlo method.

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As a possible cause of residual background in Mie scattering by a sonoluminescing single bubble, double scattering involving the bubble and surrounding small particles is examined. For reasonable values of the density and size of the particles, which are assumed to be distributed randomly and uniformly, the double scattering is estimated to contribute considearably to the ordinary Mie scattering. The theory suggests how the double-scattering contribution can be reduced.

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The three-dimensional vortical structures created in the downstream of the moderate-Reynolds-number (Re ≤ 700) backward-facing step flow are studied based on the direct numerical simulation (DNS). The flow is assumed to be periodic in the spanwise direction. The vortical structure manifests itself in the form of zig-zag arrangement of alternating quasi-streamwise structures with positive and negative streamwise vorticity, which has been observed in the buffer region of the turbulent channel flow by DNS [J. Fluid Mech. 332 (1997) 185]. In order to excite the perturbation, we triggered the flow by giving discontinuity of the time derivative of the inlet flow initially. It is found that the condition whether the three-dimensional vortical structures appear depends on the rate of temporal increase of the perturbation amplitude as t > 0. The present study is closely related to the generation mechanism of the coherent vortical structures in the wall turbulence.

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In a recent article [Yamamoto and Ikuta: J. Phys. Soc. Jpn. 68 (1999) 2602] state that the true origin of negative differential conductivity (NDC) has never been shown, in apparent contradiction of claims made in earlier papers [Z. Lj et al .: Aust. J. Phys. 37 (1984) 23; R. E. Robson: ibid. 37 (1984) 35]. In the present paper, we argue that the true origin of NDC has indeed been explained satisfactorily, and present a comprehensive range of calculations for a number of cases, demonstrating the effectiveness of momentum transfer theory [Hot electron transport in semiconductors (Springer, Berlin, 1985) p. 82] for understanding NDC from both a qualitative and quantitative perspective.

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The nonlinear saturation mechanism of the ion-ion instability is clarified. Amplitude oscillations is observed in an ion beam-plasma system with a mesh grid as a boundary condition. These amplitude oscillations are caused by multiple energy exchange between the unstable wave and trapped particles. Furthermore, the wave numbers estimated from the saturating length of ion-ion instability's wave-patterns are proportional to √V_m, where V_m represents a modulating amplitude of test waves. Thus it turns out that the ion-ion instability saturates due to particle trapping effect.

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With the aim to study the ion temperature gradient (ITG) driven turbulence, a nondissipative kinetic simulation scheme is developed and comprehensively benchmarked. The new simulation method preserving the time-reversibility of basic kinetic equations can successfully reproduce the analytical solutions of asymmetric three-mode ITG equations which are extended to provide a more general reference for benchmarking than the previous work [T.-H. Watanabe, H. Sugama and T. Sato: Phys. Plasmas 7 (2000) 984]. It is also applied to a dissipative three-mode system, and shows a good agreement with the analytical solution. The nondissipative simulation result of the ITG turbulence accurately satisfies the entropy balance equation. Usefulness of the nondissipative method for the drift kinetic simulations is confirmed in comparisons with other dissipative schemes.

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Temperature variation of the crystal structure has been investigated for Tb₂Ba₂Co₄O₁₁, which shows a metal-insulator (MI) transition at T_MI = 340 K. The compound has a layered-type double-perovskite structure along the c-axis, with alternating the CoO₆ octahedron and the CoO₅ pyramids along the a-axis. With decrease of temperature below T_MI, the distortion of the octahedral and pyramidal sites is fairly released, suggesting that spin state transition of the Co³⁺ ions is the origin for the MI transition.

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The differential scanning calorimetry and thermogravimetry of KHCO₃ indicate new transformation anomalies at 155 K (T_c2), 373 K (T_d) and 459 K. The former anomaly is likely to be caused by a structural phase transition, but the latter two anomalies are related to the thermal decomposition. The chemical reaction begins at about 373 K (T_d) and reaches a complete thermal decomposition of KHCO₃ into K₂CO₃ around 459 K. The experimental results are discussed in terms of protonic intrabond and interbond jump.

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The temperature dependence of ionic conductivity of the AgI films on SiO₂ glass (quartz grass) substrates has been measured for various film thickness. AgI thin films showed conductivity enhancement, and the ionic conductivity shows an increase with decreasing the thickness. The experimental results suggest the existence of the high ionic conduction region at the SiO₂-AgI boundary. The thickness dependence of ionic conductivity of the AgI film was explained by a simple two layer model; high ionic conduction region and bulk ionic conduction region. Average ionic conductivity σ_λ and thickness λ of the high ionic conduction region at 300 K were estimated as 4.65 × 10^-5 Ω^-1cm^-1 and 0.28 μm, respectively.

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The molecular dynamics simulations are carried out in a liquid AuCs alloy. The electrical conductivities are obtained by using the equilibrium and non-equilibrium molecular dynamics methods, and these results agree well with experimental conductivities. The deviation from the Nernst-Einstein relation Δ is also derived by equilibrium molecular dynamics, using the partial conductivities σ⁺ and σ^-, and the self diffusion coefficients D⁺ and D^- of cations and anions, respectively. The obtained value of Δ is negative as that of molten AgI, potassium iodine and rubidium halides, which is related to the cross-correlation of ionic motion.

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Unique structural phase evolution was observed in the nano-sized Co-Cu multilayers upon solid-state reaction/ion beam mixing and resulted in the formation of several metastable phases in the equilibrium immiscible Co-Cu system. Despite of a positive heat of formation of the Co-Cu system, a superlattice was obtained in the nano-sized Co₃₄Cu₆₆ multilayered films upon 600 K thermal annealing, and it later evolved into a dodecagonal phase when the annealing temperature was risen up to 800 K. Comparatively, by ion beam mixing, other metastable phases were obtained, e.g., an amorphous phase and a dodecagonal phase were obtained in the Co₁₅Cu₈₅ films. The same dodecagonal phase was also formed in the Co₅₀Cu₅₀ films and the ion mixed dodecagons tended to assemble themselves into a fourfold rotational symmetry at relatively high irradiation dose. In the present paper, thermodynamic modeling and the formation mechanism of the metastable phases were also discussed based on Miedima's model and consideration of the physical process driven far-from-equilibrium by ion beam mixing.

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Phase diagram of the one-dimensional extended Hubbard model with a nearest neighbor interaction V and site-off-diagonal (bond-charge X and bond-bond W) interactions at half-filling is obtained analytically and numerically. For the numerical analysis, we used the level-crossing approach which has been applied to the W=0 case [Phys. Rev. B 61 (2000) 16377]. Similarly to the X term, the W term enhances bond-charge-density-wave (BCDW) and bond-spin-density-wave (BSDW) phases for W<0 and W>0 cases, respectively. In addition, we showed that an exact ground state corresponding to a BSDW state, and an η-pairing ground state appear in this model.

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Self-consistent band calculation of sodium is performed in the correlated Hartree-Fock scheme proposed by Yasuhara and Takada [Phys. Rev. B 43 (1991) 7200], which contains information on the effective mass of the electron liquid in the form of a nonlocal spin-parallel potential, and the remaining information of the self-energy operator in the form of a local potential. The bandwidth of occupied states is somewhat increased under the influence of the non-local spin-parallel potential, compared with the free electron value. No significant difference can be found in the distortion of the Fermi surface between the present theory and the LDA.

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In this paper, one dimensional system of Dirac fermions with a random-varying mass is studied by the transfer-matrix method. We investigate the effects of nonlocal correlation of the spatial-varying Dirac mass on the delocalization transition. In particular, we numerically calculate both the “typical” and “mean” localization lengths as a function of energy and the correlation length of the random mass. To this end we introduce an imaginary vector potential as suggested by Hatano and Nelson and solve the eigenvalue problem. Numerical calculations are in good agreement with the results of the analytical calculations. We obtain a relation between the localization length of states and the correlation length of the random mass.

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The quasi-particle tunneling phenomena in the paired fractional quantum Hall states are studied. A single point-contact system is first considered. Because of relevancy of the quasi-particle tunneling term, the strong tunneling regime should be investigated. Using the instanton method it is shown that the strong quasi-particle tunneling regime is described as the weak electron tunneling regime effectively. Expanding to the network model the paired quantum Hall liquid to insulator transition is discussed.

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We analytically study the photorefractive Gunn effect in n-GaAs subjected to two external laser beams which form a moving interference pattern (MIP) in the semiconductor. When the intensity of the spatially independent part of the MIP, denoted by I₀, is small, the system has a periodic domain train (PDT), consistent with the results of linear stability analysis. When I₀ is sufficiently large, the space-charge field induced by the MIP will compete with the PDT and result in complex dynamics, including driven chaos via quasiperiodic route.

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Scattering of an electron wave by a cap is studied for several types of caps attached to a metallic armchair nanotube in an effective-mass approximation. The scattering phase shifts are expressed in terms of the shift in the boundary position and the effective phase shift at the boundary. The boundary shift is given by about 0.24 times the distance between the cap boundary and the cap tip, and the effective phase shift to be 0 and π for waves in the state with parity - and +, respectively.

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We present the results of electrical resistivity ρ, Hall coefficient R_H, thermoelectric power S, specific heat C and magnetic susceptibility χ on SmBiPt with the MgAgAs-type structure. ρ(T) and S(T) exhibit a broad maximum of 1.7 mΩcm at 80 K and 60 μV/K at 126 K, respectively. These facts and the change of R_H from negative to positive on cooling through 200 K indicate the semimetallic nature of SmBiPt. At around 7 K, ρ(T) and S(T) show a shallow dip and a small peak, respectively. The antiferromagnetic order at T_N= 2.2 K is manifested as a sudden drop in ρ and a peak in both C and χ. The magnetic entropy at T_N is 0.6Rln4 and reaches a plateau of Rln4 at 18 K, indicating the Γ₈ quartet ground state of Sm³⁺ in this cubic compound. The results of χ(T) and magnetization curve can be explained by considering the mixing of higher multiplet levels of J=7/2 and 9/2 into the ground multiplet of J=5/2.

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We investigate the dynamics of o-p conversion of H₂ scattered from a 3d impurity sitting on a metal oxide surface. We treat Fermi's contact interaction (intra-molecular hyperfine contact interaction) and the H₂-surface electron exchange interaction (Coulomb interaction) as perturbations. Numerically, we calculate the o-p H₂ conversion yield as functions of the H-H bond orientation with respect to the surface normal and translational energy of H₂. We find that the o-p H₂ conversion yield decreases exponentially with increasing translational energy, and strongly depends on the H-H bond orientation with respect to the surface normal. The o-p H₂ conversion yield shows that a perpendicular orientation is preferred over a parallel orientation.

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We developed a method of precise measurement of the dielectric constant under multi-extreme conditions, that is, under high pressures, high magnetic fields and low temperatures. We measured the dielectric constants and the magnetic susceptibility of single crystals of α^′-NaV₂O₅ under multi-extreme conditions. Anisotropic behavior of a relative dielectric constant was observed at the charge-ordering transition temperature under ambient pressure. With increasing hydrostatic pressure, the transition temperature decreased and another transition appeared below the first transition temperature. The susceptibility exhibited a sharp drop corresponding to the transition to the spin singlet state at the first transition temperature, while it showed no anomaly at the second transition temperature. These two transition temperatures were found to exhibit very weak magnetic field dependence in comparison with typical spin-Peierls compounds.

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A combination of the dense Kondo effect and Ruderman-Kittel-Kasuya-Yoshida interaction exhibited by an antiferromagnetic (AF) heavy-Fermion compound CeCuSb₂ (T_N=8 K) was investigated with the magnetic susceptibility χ and ⁶³Cu magnetic resonance measurements in the temperature range between 1.4 and 210 K. For temperatures above ∼25 K, characteristics of the localized 4f spins are observed in the Curie-Weiss-type behavior of the Knight shift K and the strongly enhanced relaxation rate T₁^-1. For the temperature below ∼25 K, the χ data tend toward a constant value, which is an indication of the onset of the heavy-Fermion state. The slope of the Knight shift versus susceptibility (K-χ) plots decreases below ∼100 K, which is ascribed to the difference in the anisotropic hyperfine coupling to the crystal-field-split Γ₇ (ground state) and Γ₈ (excited state) wave functions of the Ce ions. The K-χ plots below ∼25 K exhibit another deviation from the linearity in opposite direction. We speculate that this is caused by the spin polarization of the conduction electron cloud associated with the Kondo-like compensation of the Ce's 4f moment. The low-temperature increase of T₁^-1 is conjectured to the development of short range magnetic ordering at temperatures well above T_N. Below T_N, we observed a large anisotropic broadening of the resonance line and an abrupt decrease of T₁^-1. The experimental values of the linewidth for T«T_N and the hyperfine field give a measure of the partial moment compensation by about 23%, which can reasonably be compared with the small magnetic entropy S_mag of 0.7ln2. In a related superconducting compound LaCuSb₂ (T_SC=0.9 K), on the other hand, both of K and (T₁T)^-1 for each of ⁶³Cu and ¹²¹Sb exhibit near temperature-independent behavior of the normal Fermi liquid, and the small values are indicative of rather low density of carriers.

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The magnetization process of the S=1 and 1/2 kagomé Heisenberg antiferromagnet is studied by means of the numerical exact diagonalization method. It is found that the magnetization curve at zero temperature has a plateau at 1/3 of the full magnetization. In the presence of √3 × √3 lattice distortion, this plateau is enhanced and eventually the ferrimagnetic state is realized. There also appear the minor plateaux above the main plateau. The physical origin of these phenomena is discussed.

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The magnetization process of one-dimensional Kondo necklace model with next-nearest-neighbor interaction has been studied by the use of exact-diagonalization method. The magnetization plateaus appear at zero (m=0) and at half (m=1/2) of the saturation magnetization. The ground state in the absence of a magnetic field is regarded as an aggregate of intra-atomic Kondo singlets. On the other hand, the spin configuration at the 1/2-plateau represents the intra-chain dimer (σ-dimer) phase with broken translational symmetry. The picture for spin configurations in the uniform magnetic fields other than m=0 and 1/2 are also given. We also determined the phase diagram for the ground state of the system in the magnetic field.

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Although the crystal-field ground state in the paramagnetic phase of CeP is Γ₇, part of cerium ions take a Γ₈-like state in magnetically ordered phases and regular arrangements of the Γ₇ and Γ₈-like moments constitute magnetic structures. We have performed transverse magnetoresistance measurements up to 32 T for selected field directions and have determined phase boundaries related to the appearance of the Γ₈-like state for each field direction. The result reveals the extreme uniaxial anisotropy that the Γ₈-like moment is strongly bound to the [001] axis. We have also determined the field-orientation dependence of phase transitions connected with the rearrangement of the Γ₇ moment via ac susceptibility measurements. The analysis of the angular dependence indicates that the Γ₇ moment prefers the [001] direction only weakly probably due to the exchange field from neighboring Γ₈ moments. The resistivity exhibits a sharp decrease on the appearance of the Γ₈-like state. Besides, Hall effect measurements up to 26 T show a concomitant reduction of the magnitude of the Hall coefficient, and suggest the presence of the anomalous Hall effect in the magnetically ordered phases. These indicate that the appearance of the Γ₈-like state is accompanied by a drastic change of the electronic structure.

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Thermodynamic properties of the S=1/2 Heisenberg chain in transverse staggered magnetic field H_s^y and uniform magnetic field H^x perpendicular to the staggered field is studied by the finite-temperature density-matrix renormalization-group method. The uniform and staggered magnetizations and specific heat are calculated from zero temperature to high temperatures up to T=4J under various strength of magnetic fields H_s^y and H^x. The specific heat and magnetization of the effective Hamiltonian of the Yb₄As₃ are also presented, and field induced gap formation and diverging magnetic susceptibility at low temperature are shown.

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Ordering of the geometrically frustrated two-dimensional Heisenberg antiferromagnet on a pyrochlore slab is studied by Monte Carlo simulations. The model is expected to serve as a reference system of SrCrGaO compound studied extensively. In sharp contrast to the kagomé Heisenberg antiferromagnet, the model exhibits locally non-coplanar spin structures at low temperatures, bearing nontrivial chiral degrees of freedom. We find that under certain conditions the model exhibits a novel Kosterlitz-Thouless-type transition at a finite temperature associated with these chiral degrees of freedom. Implications to experiments are discussed.

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The ¹H and ⁸⁷Rb NMR spin-lattice relaxation times for a RbHSO₄ single crystal were measured in the temperature range of 300-170 K for study of the paraelectric (I) to ferroelectric (II) phase transition near T_c=264 K. Proton spin-lattice relaxation time on the RbHSO₄ yielded a minimum, attributed to the effect of molecular motion. The activation energy for the reorientational motion in phase I was determined to be 16.54 kJ/mol, whereas, for the molecular motion in the phase II it was 25.53 kJ/mol. The change of the ⁸⁷Rb spin-lattice relaxation rate near 264 K corresponds to a phase transition in the crystal. The temperature dependences of the relaxation rate for ⁸⁷Rb in this crystal were in accordance with the single phonon process dominated by the phonon mechanism. The activation energies in phases I and II were obtained to be 2.66 kJ/mol and 17.25 kJ/mol, respectively. From ¹H and ⁸⁷Rb NMR investigations, the phase transition does play an important role by Rb nucleus, although the activation energy obtained by ¹H relaxation time is higher than that obtained by ⁸⁷Rb relaxation time.

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Mössbauer spectra of a single crystal of LuFeCoO₄ are studied in the temperature range between 4.2 K and 70 K. The Mössbauer spectra are separated into two components. We propose a model that one of three spins in a spin plane is parallel to the c-axis and other two orient to 120^º to the c-axis. This model explains the experimental data satisfactory. It is concluded that the spins parallel to the c-axis are more stable than the other when temperature is increased. The Ising like character observed in susceptibility measurements can be explained by this spin arrangement in the spin planes.

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Continued fraction representation is reviewed in magneto-optical transition of electrons in semiconductors interacting with acoustic phonons in the quantum limit. The representation is obtained by utilizing Mori's projectors and is changed into the power series form in the lowest order approximation. The expansion parameter appearing in the transformation is examined with focus on the difference between the piezoelectric scattering and the deformation potential scattering. In the present choice of expansion, the parameter for CdS and GaAs decreases monotonously with temperature, unlike for Ge and Si, for which the parameter is a common constant.

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We fabricated CuCl quantum dots (QDs) in a glass matrix. The blue shift of the exciton spectrum caused by quantum confinement effects was observed in the linear absorption and the photo-luminescence (PL) spectrum. Inhomogeneous line broadening was mainly induced by the size distribution of CuCl QDs and we found that the size distribution has Gaussian profiles. By solving the steady state rate equation, we also found that the intensities of biexciton PL were proportional to the square of exciton PL intensities, and the results were well accorded with the experimental results. The formation rates of biexciton were proportional to the volumes of CuCl QDs.

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The C=C stretching modes in resonance Raman spectra and infrared reflectivity were measured at temperatures between 15 K and 300 K using various polarizations in κ-(BEDT-TTF)₂Cu[N(CN)₂]Br, its fully and partially deuterated analogues, and ¹³C-substituted analogue. The infrared- and Raman-active bands were re-assigned based on the factor group analysis. We found a Raman-active EMV-coupled ν₃ mode near 1420 cm^-1, which shows a large downshift and broadening through the inter-dimer EMV interaction. The mixing of the bridge and ring C=C stretching vibrations depend upon the symmetry of the crystal mode. In contrast to deuterated crystals, the non-deuterated crystals show a splitting in the ν₂, ν₃, and ν₂₇ bands.

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Crystal and magnetic structures of Tb_1-xCa_xMnO₃ (x ≥ 0.5) have been investigated by means of neutron powder diffraction experiments. We have derived the magnetic phase diagram against hole concentration x and temperature T: the spin structure changes as CE- → C- → G-type structure with increase of x. In the vicinity of the magnetic phase boundaries, magnetically phase separated state has been observed. At high temperature region, we observe the metallic behavior in a wide x region (0.70 ≤ x ≤ 0.95), and ascribe it to the enhanced one-electron bandwidth W of the e_g state.

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Cell automaton simulations have been performed for the traffic flows on two one-lane roads, crossing at a point, where the maximum velocities of the northbound and the eastbound cars are different. The phase diagrams are constructed, and it has turned out that the phase diagrams consist of six regions. The obtained phase diagrams are interpreted on the basis of the local occupation probability method.

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