巻号一覧
78 巻, 8 号
選択された号の論文の56件中1～50を表示しています
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Tatsuro Yuge, Akira Shimizu2009 年 78 巻 8 号 p. 083001
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありThe fluctuation in electric current in nonequilibrium steady states is investigated by molecular dynamics simulation of macroscopically uniform conductors. At low frequencies, appropriate decomposition of the spectral intensity of current into thermal and excess fluctuations provides a simple picture of excess fluctuations behaving as shot noise. This indicates that the fluctuation–dissipation relation may be violated in a universal manner by the appearance of shot noise for a wide range of systems with particle or momentum transport.抄録全体を表示PDF形式でダウンロード (143K) -
Jong-Hoon Huh, Akiyuki Kuribayashi, Shoichi Kai2009 年 78 巻 8 号 p. 083601
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありWe report the threshold shift induced by externally applied noises for electrohydrodynamic convections (EHCs) in both planarly and homeotropically aligned nematic liquid crystals as well as in both the conduction and dielectric regimes. Owing to the difference in timescales among the intrinsic properties of EHCs, externally applied noises, and deterministic fields, the stabilization or destabilization effects induced by noises are observed. In particular, the difference in the threshold shift between both alignments is found, and discussed in terms of the EHC mechanisms for both alignments. Moreover, a noticeable noise-induced threshold shift is observed in the dielectric regime, which is markedly different from that in the conventional conduction regime.抄録全体を表示PDF形式でダウンロード (1310K) -
Taichi Terashima, Motoi Kimata, Hidetaka Satsukawa, Atsushi Harada, Ka ...2009 年 78 巻 8 号 p. 083701
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありWe report the ac magnetic susceptibility χac and resistivity ρ measurements of EuFe2As2 under high pressure P. By observing nearly 100% superconducting shielding and zero resistivity at P=28 kbar, we establish that P-induced superconductivity occurs at Tc∼30 K in EuFe2As2. ρ shows an anomalous nearly linear temperature dependence from room temperature down to Tc at the same P. χac indicates that an antiferromagnetic order of Eu2+ moments with TN∼20 K persists in the superconducting phase. The temperature dependence of the upper critical field is also determined.抄録全体を表示PDF形式でダウンロード (662K) -
Hisashi Kotegawa, Takayuki Kawazoe, Hitoshi Sugawara, Keizo Murata, Hi ...2009 年 78 巻 8 号 p. 083702
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありWe report that the pressure–temperature phase diagram of single-crystalline SrFe2As2 is easily affected by the hydrostaticity of a pressure-transmitting medium. For all of the three mediums we used, superconductivity with zero resistance appears, accompanied by the suppression of an antiferromagnetic (orthorhombic) phase, but the critical pressure Pc was found to depend on the type of medium. Pc was estimated to be 4.4 GPa under almost hydrostatic condition, but it decreased to 3.4–3.7 GPa with the use of the medium already solidified at room temperature. The uniaxial stress along the c-axis is suggested to aid in the suppression of the antiferromagnetic (orthorhombic) phase. The pressure effect of BaFe2As2 is also reported.抄録全体を表示PDF形式でダウンロード (446K) -
Jun-ichiro Ohe, Yoshihiro Tomoda, Nejat Bulut, Ryotaro Arita, Kazuma N ...2009 年 78 巻 8 号 p. 083703
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありWe present a realistic study for electronic and magnetic properties in dilute magnetic semiconductor (Ga,Mn)As. A multi-orbital Haldane–Anderson model parameterized by density-functional calculations is presented and solved with the Hirsch–Fye quantum Monte Carlo algorithm. Results well reproduce experimental results in the dilute limit. When the chemical potential is located between the top of the valence band and an impurity bound state, a long-range ferromagnetic correlations between the impurities, mediated by antiferromagnetic impurity–host couplings, are drastically developed. We observe an anisotropic character in local density of states at the impurity-bound-state energy, which is consistent with the STM measurements. The presented combined approach thus offers a firm starting point for realistic calculations of the various family of dilute magnetic semiconductors.抄録全体を表示PDF形式でダウンロード (207K) -
Katsunori Kubo, Peter Thalmeier2009 年 78 巻 8 号 p. 083704
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありWe apply a Hartree–Fock approximation to a two-orbital model proposed for Fe pnictide superconductors. It is found that the antiferromagnetic (AFM) order with the ordering vector Q=(π,0) is realized. The AFM order appears simultaneously with ferro-orbital order, the latter leads to a secondary lattice distortion. We also investigate the influence of doping on the AFM order. The size of the AFM moment changes continuously for lightly doped cases, but when the amount of doped carriers exceeds a certain value the AFM state is suddenly destroyed. We also show that Fermi surfaces remain and change significantly on doping even in the AFM state. This behaviour is explained by considering the nesting due to the multi-sheet Fermi-surface structure and multiorbital nature of the electronic bands characteristic to Fe pnictides.抄録全体を表示PDF形式でダウンロード (277K) -
Atsushi Ishizumi, Yoshihiko Kanemitsu2009 年 78 巻 8 号 p. 083705
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありWe report on the photoluminescence (PL) blinking behavior of nondoped and Mn-doped CdS/ZnS nanocrystals studied using single nanocrystal spectroscopy at room temperature. The blinking phenomenon is clearly observed in the surface-defect luminescence of nondoped single CdS/ZnS nanocrystals. In Mn-doped CdS/ZnS nanocrystals, however, PL blinking is markedly suppressed, and the Mn2+-related PL has a long on-time. Our findings indicate that Mn2+ ions are excited by fast energy transfer from photoexcited excitons in both neutral and ionized CdS/ZnS nanocrystals. We discuss energy transfer processes from the host nanocrystals to the Mn2+ ions.抄録全体を表示PDF形式でダウンロード (193K) -
Akihiro Ueda, Takeshi Tayagaki, Yoshihiko Kanemitsu2009 年 78 巻 8 号 p. 083706
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありThe dynamics of quantized Auger recombination in CdSe nanocrystals was studied by femtosecond intraband pump–probe spectroscopy at room temperature. The intraband transient absorption signals increase linearly with excitation laser intensity, while the interband transient absorption signals saturate at high excitation intensities. We clarified that the excitation intensity dependence of the Auger recombination rate in nanocrystals is quantitatively explained by three-body photocarrier collision processes.抄録全体を表示PDF形式でダウンロード (122K) -
Yuji Muro, Kiyoichiro Motoya, Yuta Saiga, Toshiro Takabatake2009 年 78 巻 8 号 p. 083707
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありWe report on the magnetic, transport, and thermal properties of a cage-like compound CeFe2Al10 that crystallizes in the orthorhombic YbFe2Al10-type structure. A broad peak in the magnetic susceptibility at 70 K indicates that CeFe2Al10 is a valence fluctuation compound. The electrical resistivity and the Hall coefficient exhibit sharp upturns below 20 K, where the thermopower shows a rapid decrease. These low-temperature anomalies in the transport properties resemble those of a typical Kondo semiconductor CeRhSb. These features indicate the formation of a hybridization gap in CeFe2Al10 on cooling below 20 K. The energy gap is estimated as 15 K from the thermal activation energy of the resistivity. The magnetic contribution of the specific heat shows a Schottky-type maximum at 30 K that provides another evidence for the gap formation in CeFe2Al10.抄録全体を表示PDF形式でダウンロード (539K) -
Fumitake Kikuchi, Katsuya Hara, Eiichi Matsuoka, Hideya Onodera, Shint ...2009 年 78 巻 8 号 p. 083708
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありSingle crystals of Yb2(Pd1−xNix)2Sn with x=0, 0.1, and 0.2 were prepared to clarify the effects of pressure on Yb2Pd2Sn which is considered to reside near the quantum critical point. The magnetization and specific heat measurements revealed that their ground states are regarded as an S=1⁄2 XY-like spin system. Although nondoped Yb2Pd2Sn shows no magnetic transition down to 0.5 K owing to the Kondo effect, Ni-doped Yb2Pd2Sn exhibits a distinct magnetic transition. Furthermore, the magnetic susceptibility of Ni-doped Yb2Pd2Sn exhibits a broad peak in the temperature range higher than the magnetic transition temperature, which is not explained by the S=1⁄2 Coqblin–Schrieffer model, suggesting the effect of geometrical frustration arising from the characteristic structure of these compounds, i.e., the Shastry–Sutherland lattice.抄録全体を表示PDF形式でダウンロード (429K) -
Hironari Okada, Hiroyuki Takahashi, Yoshikazu Mizuguchi, Yoshihiko Tak ...2009 年 78 巻 8 号 p. 083709
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありWe performed magnetization and electrical resistivity measurements under high pressures of up to 19 GPa for FeTe0.92. The compound shows an anomaly in magnetization and resistivity at atmospheric pressure due to a structural distortion accompanied by a magnetic transition. We also observed magnetic and resistive anomalies under high pressure, suggesting that two pressure-induced phases exist at a low temperature. Unlike in FeAs-based compounds, no superconductivity was detected under high pressures of up to 19 GPa, although the anomaly at atmospheric pressure was suppressed by applying pressure.抄録全体を表示PDF形式でダウンロード (496K) -
Kazuma Nakamura, Yoshihide Yoshimoto, Taichi Kosugi, Ryotaro Arita, Ma ...2009 年 78 巻 8 号 p. 083710
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありWe derive effective Hubbard-type Hamiltonians of κ-(BEDT-TTF)2X, using an ab initio downfolding technique, for the first time for organic conductors. They contain dispersions of the highest occupied Wannier-type molecular orbitals with the nearest neighbor transfer t∼0.067 eV for a metal X=Cu(NCS)2 and 0.055 eV for a Mott insulator X=Cu2(CN)3, as well as screened Coulomb interactions. It shows unexpected differences from the conventional extended Hückel results, especially much stronger onsite interaction U∼0.8 eV (U⁄t∼12–15) than the Hückel estimates (U⁄t∼7–8) as well as an appreciable longer-ranged interaction. Reexamination on physics of this family of materials is required from this realistic basis.抄録全体を表示PDF形式でダウンロード (749K) -
Haruka Oguchi, Nobuhiko Taniguchi2009 年 78 巻 8 号 p. 083711
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありMotivated by recent experiments on electronic transport through a carbon nanotube dot, we investigate the role of the intra- and inter-orbital Coulomb interactions on the temperature evolution of the conductance. It is shown that small amount (\\lesssim10%) of asymmetry between these Coulomb repulsions substantially deforms the conductance profile at finite temperature, particularly around half-filling. The nature of such thermal symmetry crossover is elucidated.抄録全体を表示PDF形式でダウンロード (671K) -
Hideto Fukazawa, Yuji Yamada, Kenji Kondo, Taku Saito, Yoh Kohori, Ken ...2009 年 78 巻 8 号 p. 083712
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありWe report the 75As nuclear quadrupole resonance (NQR) and specific heat measurements of the heavily hole-doped superconductor KFe2As2 (superconducting transition temperature Tc\\simeq3.5 K). The spin-lattice relaxation rate 1⁄T1 in the superconducting state exhibits a gradual temperature dependence with no coherence peak below Tc. The quasiparticle specific heat CQP⁄T shows a small jump, which is about 30% of the electronic specific heat coefficient just below Tc. The CQP⁄T suggests the existence of low-energy quasiparticle excitation at the lowest measurement temperature T=0.4K\\simeqTc⁄10. The T dependences of 1⁄T1 and CQP⁄T can be explained by a multiple nodal superconducting gap scenario rather than by a multiple fully gapped s±-wave scenario determined using simple gap analysis.抄録全体を表示PDF形式でダウンロード (256K) -
Hiroyuki Nakamura, Hiroshi Tomita, Hikota Akimoto, Ryota Matsumura, Is ...2009 年 78 巻 8 号 p. 083713
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありElectrostatic carrier doping using a field-effect-transistor structure is an intriguing approach to explore electronic phases by critical control of carrier concentration. We demonstrate the reversible control of the insulator–metal transition (IMT) in a quasi-two-dimensional (2D) electron gas at the interface of insulating SrTiO3 single crystals. Superconductivity was observed in one device doped far beyond the IMT, which may imply the presence of 2D metal–superconductor transition. This realization of a quasi-two-dimensional metallic state on the most widely-used perovskite oxide is the best manifestation of the potential of oxide electronics.抄録全体を表示PDF形式でダウンロード (262K) -
On Shun Pak, Chun Kit Lam, Kaliyaperumal Nakkeeran, Boris Malomed, Kwo ...2009 年 78 巻 8 号 p. 084001
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありPulse propagation in inhomogeneous nonlinear media with linear and nonlinear gain and loss, described by a system of nonlinearly coupled complex Ginzburg–Landau equations (CGLEs) with variable coefficients, is considered. Exact solitary pulse (SP) solutions are obtained analytically, for special choices of variable coefficients of the nonlinear gain/loss terms, by a modified Hirota bilinear method. The solutions include space- or time-dependent wave numbers, which imply dilatation or compression of the SPs. Stability of the solutions is tested by means of direct simulations, which demonstrate that, in many cases, the SPs are stable against perturbations.抄録全体を表示PDF形式でダウンロード (675K) -
Shu Tanaka, Seiji Miyashita2009 年 78 巻 8 号 p. 084002
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありWe study a slow relaxation process in a frustrated spin system in which a type of screening effect due to a frustrated environment plays an important role. This screening effect is attributed to the highly degenerate configurations of the frustrated environment. This slow relaxation is due to an entropy effect and is different from those due to the energy barrier observed in systems such as random ferromagnets. In the present system, even if there is no energy gap, the slow relaxation still takes place. Thus, we call this phenomenon “entropic slowing down”. Here, we study the mechanism of entropic slowing down quantitatively in an Ising spin model with the so-called decorated bonds. The spins included in decorated bonds (decoration spins) cause a peculiar density of states, which causes on entropy-induced screening effect. We analytically estimate the time scale of the system that increases exponentially with the number of decoration spins. We demonstrate the scaling of relaxation processes using the time scale at all temperatures including the critical point.抄録全体を表示PDF形式でダウンロード (660K) -
Kazuyuki Ogata, Takuma Matsumoto, Yasunori Iseri, Masanobu Yahiro2009 年 78 巻 8 号 p. 084201
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありThe dependence of breakup cross sections of 8B at 65 MeV/nucleon on the target mass number AT is investigated by means of the continuum-discretized coupled-channels method (CDCC) with more reliable distorting potentials than those in the preceding study. The AT1⁄3 scaling law of the nuclear breakup cross section is found to be satisfied only in the middle AT region of 40\\lesssimAT\\lesssim150. The interference between nuclear and Coulomb breakup amplitudes vanishes in very forward angle scattering, independently of the target nucleus. The truncation of the relative energy between the p and 7Be fragments slightly reduces the contribution of nuclear breakup at very forward angles, while the angular region in which the first-order perturbation theory works well does not change essentially.抄録全体を表示PDF形式でダウンロード (125K) -
Myung-Ki Cheoun, Kyungsik Kim2009 年 78 巻 8 号 p. 084202
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありStrange quark contributions to elastic neutrino–nucleon scattering and neutrino–nucleus scattering for 12C target in quasi-elastic region are investigated on the incident energy of 500 MeV within the framework of a relativistic single particle model. For the neutrino–nucleus scattering, the effects of final state interaction for the knocked-out nucleon are included by a relativistic optical potential. In the cross sections for neutrino–nucleus scattering we found some cancellations of the strange quark contributions in the knocked-out proton and neutron process. Consequently, the asymmetries between the incident neutrino and antineutrino, which are given by the ratio of neutral current to charged current, and a difference between the asymmetries are shown to be more feasible quantities for the strangeness effects. In order to explicitly display the importance of such cancellations, results of the exclusive reaction 16O(ν,ν′p) are additionally presented for detecting the strangeness effects.抄録全体を表示PDF形式でダウンロード (172K) -
Kou Matsui, Takahiko Shobu, Yasunori Tanami, Hiroki Nakamatsu, Hideki ...2009 年 78 巻 8 号 p. 084301
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありWe have developed an apparatus for creating Bose–Einstein condensates of sodium atoms. Radio-frequency-induced forced evaporative cooling was studied experimentally and optimized to stably create sodium condensates containing a large number of atoms. The transition temperature, the spatial distribution of the condensate, and the aspect ratio of the Bose–Einstein condensate were analyzed quantitatively and compared with theoretical predictions. Several methods of ramping down the rf for evaporative cooling were tested.抄録全体を表示PDF形式でダウンロード (2187K) -
Seo Ro Shin, Heung-Ryoul Noh2009 年 78 巻 8 号 p. 084302
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありWe present an experimental and theoretical study of the transmission of a π (or σ+) polarized laser beam for a Doppler broadened rubidium vapor cell. The transmission of the laser beam for the D2 transition line of 85Rb atoms was measured as a function of the laser frequency for various laser intensities. The observed spectra were compared with calculation, taking into account both the Gaussian beam profile and the fact that atoms were measured while crossing the laser beam. We found excellent agreement between the experimental and calculated results. We also investigated different operating mechanisms of variation of transmission for each transition line.抄録全体を表示PDF形式でダウンロード (216K) -
Sotos Constantinou Generalis, Kaoru Fujimura2009 年 78 巻 8 号 p. 084401
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありIn this paper we examine the equilibrium states of finite amplitude flow in a horizontal fluid layer with differential heating between the two rigid boundaries. The solutions to the Navier–Stokes equations are obtained by means of a perturbation method for evaluating the Landau constants and through a Newton–Raphson iterative method that results from the Fourier expansion of the solutions that bifurcate above the linear stability threshold of infinitesimal disturbances. The results obtained from these two different methods of evaluating the convective flow are compared in the neighborhood of the critical Rayleigh number. We find that for small Prandtl numbers the discrepancy of the two methods is noticeable.抄録全体を表示PDF形式でダウンロード (400K) -
Youhei Fujitani2009 年 78 巻 8 号 p. 084402
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありIn terms of the steady Stokes approximation, we consider flow fields around a circular pore of a flat and incompressible fluid-membrane, which is surrounded by a three-dimensional fluid. Pore size changes because of the line tension of the pore perimeter and the in-plane stress of the membrane. The pressure difference across the membrane causes a three-dimensional flow through the pore. The dependence of its volumetric flow rate on the difference between the pressure far from the membrane on its one side and that on the other side is found to be the same as obtained previously for a pore of a solid plate. We derive a differential equation for the time evolution of pore size, considering the viscosity of the surrounding fluid.抄録全体を表示PDF形式でダウンロード (116K) -
Yeontaek Choi, Sang Gyu Jo, Ho Il Kim, Sergey V. Nazarenko2009 年 78 巻 8 号 p. 084403
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありWe derive the time evolution of the two-mode amplitude probability density function. Using this equation, we derive conditions for the existence of a zero flux steady-state solution. We also derive the equation for a vortex solution and show that the product of two one-mode steady-state solutions can be a two-mode steady-state solution only when an extra condition is satisfied. With this extra condition assumed, we plot the flux of probability vector on two mode’s plane. It is shown that this flux lines circulate around the center (na,nb), which are the mean values of the two mode’s amplitude square.抄録全体を表示PDF形式でダウンロード (130K) -
Critical Velocity for the Collapse of a Cavity Region in a Granular Material and Its Size DependenceShin Koizumi, Yukio Shirahashi, Osamu Sano2009 年 78 巻 8 号 p. 084404
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありAn experiment on the collapse of a two-dimensional macroscopic cavity region in a granular material due to a viscous flow was performed. The cavity was destroyed above a certain magnitude of fluid velocity depending on the hardness of the granular assembly and was filled with the fluidized granular material. For a given granular material, the rate of cavity filling was measured under various flow magnitudes, and the critical velocity Uc, above which the collapse of cavity occurs, was determined. The dependence of Uc on the cavity size D was obtained.抄録全体を表示PDF形式でダウンロード (118K) -
Vladimir Milosavljevic, Dusan Popovic, Albert R. Ellingboe2009 年 78 巻 8 号 p. 084501
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありThe time-dependent spatial electron density distribution in a constricted, pulsed plasma source is measured using a floating hairpin resonance probe, and an extrapolation method is described for determining peak electron density from experimental data. Using these techniques, a detailed characterization of the spatio-temporal evolution of electron density, outside the constricted region above the anode of the pulsed plasma source is presented. Electron density increases sharply during the creation phase, and the rate of increase is found to decrease with the distance from the axis of the constricted channel. By modeling the plasma creation characteristics vs position, the electron density along the axis of the constricted pulsed plasma sources can be determined.抄録全体を表示PDF形式でダウンロード (316K) -
Isao Ishii, Takahiro Fujita, Ikuko Mori, Hitoshi Sugawara, Masahito Yo ...2009 年 78 巻 8 号 p. 084601
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありTo clarify the origin of ultrasonic dispersion due to the so-called rattling motion in LaFe4Sb12, we measured the temperature dependences of elastic moduli and ultrasonic attenuation. We found the ultrasonic dispersion to be between 35 and 80 K in all elastic moduli, suggesting no-mode-selectivity of ultrasound. Experimental results and theoretically calculated density of states indicate that the d-electronic states of transition metal ions play an important role in ultrasonic dispersion. The theory based on the coupling between an acoustic phonon and some optical phonons interacting with electrons is compatible with no-mode-selective ultrasonic dispersion, and it suggests a stronger electron–phonon coupling in all elastic modes in LaFe4Sb12. Low-temperature elastic softening was observed in all elastic moduli, and it continues down to 0.4 K. There is a possibility that low-temperature softening originates from quantum tunneling motion or a novel quantum effect of rattling motion.抄録全体を表示PDF形式でダウンロード (650K) -
Masakazu Takata, Tetsuo Yamaguchi, Jian Ping Gong, Masao Doi2009 年 78 巻 8 号 p. 084602
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありSliding friction of a charged gel on a substrate was investigated by applying electric voltage between gel and the substrate. It is found that the sliding friction increases markedly with the increase of the applied voltage; the friction coefficient increased by a factor of about 10 when 70 V voltage is applied. This voltage dependence of frictional force is explained by using the adhesion friction model proposed by Schallamach.抄録全体を表示PDF形式でダウンロード (318K) -
Masaru Tsukada, Kunihiro Mitsutake2009 年 78 巻 8 号 p. 084701
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありDissipating electron transfer processes between the electrodes and a molecule due to the coupling to the external degrees of freedom are theoretically analyzed. Important information is shown to be included in the energy loss spectral function, which is expressed formally in the same form for the two cases of the coupling with the molecular vibration and with the electro-magnetic environment. Magnitude of zero-bias anomaly, i.e., suppression of the conductance around zero bias region is given by the integrated function of the energy loss spectral function and the reduction ratio at the zero bias is obtained by the Debye–Waller type factor. For the case of coupling to the molecular vibration, the first-principles DFT method is applied for the calculation of the energy loss spectral function. A crucial role of the energy loss spectral function for determining the net current and the average charge of the molecule is discussed in the dissipating electron transfer regime. The relation of the present theory with the Marcus theory is discussed.抄録全体を表示PDF形式でダウンロード (1790K) -
Yasumasa Tsutsumi, Kazushige Machida2009 年 78 巻 8 号 p. 084702
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありIn order to help detecting superfluidity, we theoretically investigate p-wave pairing superfluids in neutral Fermion atom gases confined by a three dimensional (3D) harmonic potential. The Ginzburg–Landau framework, which is generic for p-wave superfluids, is used to describe the order parameter spatial structure, or texture characterized by the l-vector both at rest and under rotation. The l-vector configuration is strongly contrained by the boundary condition due to a trap. It is found that the ground state textures exhibit spontaneous supercurrent at rest both cigar and pancake shape traps. The current direction depends on the trapping shape. Under rotation a pair of half-quantum vortex with half-winding number enters a system and is stabilized for both trap geometries. We give detailed explanation for their 3D structure. The deformations of the condensate shape are seen with increasing the rotation speed, which is tightly connected with the underlying vortex formation where the condensates are depressed in the vortex core.抄録全体を表示PDF形式でダウンロード (6110K) -
Kiminori Hattori2009 年 78 巻 8 号 p. 084703
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありThere exists a direct connection between spin torque and spin current in two-dimensional electron systems with linear in momentum Rashba spin–orbit (SO) coupling. In terms of the spin-current continuity equation, we show that the spin torque of this type generates a divergent spin current due to spin injection, which we call the spin-current-driven spin pumping. We quantitatively investigate the spin pumping from SO coupled systems in contact with spin-polarized reservoirs using the nonequilibrium Green’s function formalism, demonstrating that the spin torque effect efficiently produces a pure spin current which is orders of magnitude larger than the spin Hall current.抄録全体を表示PDF形式でダウンロード (2032K) -
Keisuke Tomiyasu, Kazumasa Horigane, Toshio Yokobori, Yusuke Kousaka, ...2009 年 78 巻 8 号 p. 084704
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありWe studied magnetic phase diagram and x-dependence of spiral spin correlation in magnetically ordered phase of (Co1−xZnx)Cr2O4 by magnetization and neutron scattering experiments. The spiral correlation survives in a wide x range from 0 to 0.9. As x increases, the correlation length decreases from ξ∼23 Å at x=0, and saturates at ξ∼2.5 Å at around x=0.75, which is close to the nearest neighboring Cr3+-Cr3+ distance. The pitch is almost constant from x=0 to 0.75, then abruptly shortens above around x=0.75. The correlation is isotropic at x=0.25 but anisotropic at x=0.75. We discuss that the spiral correlation is of short-range owing to unquenched geometric frustration, and begins to collapse with the minimization of correlation length above around x=0.75, possibly as the precursor of dynamic spin hexamer caused by high geometric frustration.抄録全体を表示PDF形式でダウンロード (247K) -
Emi Minamitani, Hiroshi Nakanishi, Wilson Agerico Diño, Hideaki ...2009 年 78 巻 8 号 p. 084705
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありWe calculate the corresponding differential conductance (dI⁄dV) spectra from scanning tunneling spectroscopy (STS) measurements for two magnetic atoms adsorbed on a metal surface. The formula for the dI⁄dV spectra is based on a model that explicitly takes into account the energy dependence of the electron tunneling matrices between the corresponding constituent components, viz., the magnetic adatoms and metal surface. We find that the shape of the dI⁄dV spectra varies with the distance between the two magnetic adatoms. From considerations of the Ruderman–Kittel–Kasuya–Yosida (RKKY) interaction strength on the metal surface, we conclude that the ferromagnetic RKKY interaction sharpens the dI⁄dV peak structure, making it more pronounced. On the other hand, the antiferromagnetic RKKY interaction broadens the peak structure. This result agrees well with experimental results and confirms that the RKKY interaction causes the deformation of the observed STS peak structure.抄録全体を表示PDF形式でダウンロード (403K) -
Zhuohui Yang, Jun Wang, Kwok Sum Chan2009 年 78 巻 8 号 p. 084706
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありWe report a theoretical study on the tunneling conductance of two-dimensional electron gas/insulator/noncentrosymmetric superconductor (SC) junction, in which Rashba spin–orbital coupling (RSOC) exists in both sides of the junction and the SC lead has a mixed singlet and triplet superconducting correlation. Employing the extended Blonder–Tinkham–Klapwijk formalism, we found that RSOC in either side of the junction can enhance or suppress the conductance, depending on the junction parameters such as the Fermi wave-vectors of the leads and the insulator barrier strength between the two leads. This is different from the effect of a ferromagnetic lead. It is also found that the conductance spectra exhibit distinctive peaks and turning points, which are very useful for determining the relative strength of the singlet and triplet gaps of the SC lead, as well as the RSOC constant of the noncentrosymmetric SC from tunneling conductance measurements.抄録全体を表示PDF形式でダウンロード (254K) -
Takahiro Misawa, Youhei Yamaji, Masatoshi Imada2009 年 78 巻 8 号 p. 084707
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありWe propose a phenomenological spin fluctuation theory for antiferromagnetic quantum tricritical point (QTCP), where a first-order phase transition changes into a continuous transition at zero temperature. Under magnetic fields, ferromagnetic quantum critical fluctuations develop around the antiferromagnetic QTCP in addition to antiferromagnetic fluctuations, which is in sharp contrast with the conventional antiferromagnetic quantum critical point. For itinerant electron systems, we show that the temperature dependence of critical magnetic fluctuations around the QTCP is given as χQ∝T−3⁄2 (χ0∝T−3⁄4) at the antiferromagnetic ordering (ferromagnetic) wave number q=Q (q=0). The convex temperature dependence of χ0−1 is a characteristic feature of the QTCP, which has never been seen in the conventional spin fluctuation theory. We propose a general theory of quantum tricriticality that has nothing to do with the specific Kondo physics itself, and solves puzzles of quantum criticalities widely observed in heavy-fermion systems such as YbRh2Si2, CeRu2Si2, and β-YbAlB4. For YbRh2Si2, our theory successfully reproduces quantitative behaviors of the experimentally obtained ferromagnetic susceptibility and magnetization curve when suitable phenomenological parameters are chosen. The quantum tricriticality is also consistent with singularities of other physical properties such as specific heat, nuclear magnetic relaxation time 1⁄T1T, and the Hall coefficient. For CeRu2Si2 and β-YbAlB4, we point out that the quantum tricriticality is a possible origin of the anomalous diverging enhancement of the uniform susceptibility observed in these materials.抄録全体を表示PDF形式でダウンロード (595K) -
Koji Kobayashi, Tomi Ohtsuki, Keith Slevin2009 年 78 巻 8 号 p. 084708
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありWe study the transport properties of disordered two-dimensional electron systems with a perfectly conducting channel. We introduce an asymmetric Chalker–Coddington network model and numerically investigate the point-contact conductance. We find that the behavior of the conductance in this model is completely different from that in the symmetric model. Even in the limit of a large distance between the contacts, we find a broad distribution of conductance and a non-trivial power law dependence of the averaged conductance on the system width. Our results are applicable to systems such as zigzag graphene nano-ribbons where the numbers of left- and right-going channels are different.抄録全体を表示PDF形式でダウンロード (531K) -
Yoshitaka Uratani, Tatsuya Shishidou, Tamio Oguchi2009 年 78 巻 8 号 p. 084709
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありMagnetic anisotropy energies (MAE) of multiferroic PbVO3 and BiCoO3 are evaluated from first-principles density functional calculations. Even though both oxides have similar crystal and electronic structures, calculated easy axes of spin are different: [110] in PbVO3 and [001] in BiCoO3. To explain the difference, the origin of MAE is discussed with a perturbation theory by taking into account of the electronic structure obtained by the first-principles calculations.抄録全体を表示PDF形式でダウンロード (213K) -
Chien-Lung Huang, Chih-Chieh Chou, Kuo-Feng Tseng, Yi-Lin Huang, Fong- ...2009 年 78 巻 8 号 p. 084710
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありThe pressure (P) dependence of AC susceptibility and electrical resistivity of FeSe0.88 and FeSe0.5Te0.5 has been studied. The superconducting transition temperature (Tc) of FeSe0.5Te0.5 is found to be more sensitive to P than it is in FeSe0.88, which is believed to arise from the strongly distorted structure. The enhancement of Tc by P is mainly attributed to an increase of density of states, which implies that the superconductivity in FeSe1−xTex favors pairing mechanism in the context of strong-coupling BCS theory.抄録全体を表示PDF形式でダウンロード (320K) -
Nguyen Duc Dung, Tatsuma D. Matsuda, Yoshinori Haga, Shugo Ikeda, Etsu ...2009 年 78 巻 8 号 p. 084711
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありWe succeeded in growing high-quality single crystals of a valence fluctuating compound YbCu2Si2 and a divalent compound YbCu2Ge2. The magnetic susceptibility of YbCu2Si2 follows the Curie–Weiss law with Yb3+ at high temperatures, but reveals a broad peak around 40 K for H||[100], which is due to the formation of a 4f-itinerant heavy fermion state at lower temperatures. This is also reflected in the temperature dependence of Hall coefficient, thermoelectric power and thermal expansion. The corresponding de Haas–van Alphen (dHvA) branches are approximately explained by the 4f-itinerant LDA band model, and the 4f-itinerant LDA+U model is found to be much applicable to the dHvA data. The cyclotron effective masses of main Fermi surfaces are relatively large, being 30–40 m0, which is consistent with the electronic specific heat coefficient γ=150 mJ/(K2·mol). These results indicate that the localized 4f electrons at high temperatures become itinerant at low temperatures, forming a narrow renormalized conduction band. On the other hand, YbCu2Ge2 is a divalent compound, indicating a Pauli paramagnetic susceptibility and a small γ value of 9–10 mJ/(K2·mol). The corresponding 4f bands in YbCu2Ge2 are located below the Fermi energy, and do not contribute to the Fermi surfaces. The dHvA data are thus well explained by the Yb2+ band model. These Fermi surfaces in YbCu2Si2 and YbCu2Ge2 are highly different from the Fermi surfaces of a non-4f reference compound YCu2Si2 and a 4f-closed reference compound LuCu2Si2.抄録全体を表示PDF形式でダウンロード (5150K) -
Fusayoshi J. Ohkawa2009 年 78 巻 8 号 p. 084712
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありSuperconductivity in the cuprate oxide is studied by Kondo-lattice theory based on the t–J model with the electron–phonon interaction arising from the modulation of the superexchange interaction by phonons. The self-energy of electrons is decomposed into the single-site and multisite self-energies. It is proved by using the mapping of the single-site self-energy in the t–J model to its corresponding one in the Anderson model that the single-site self-energy is simply that of a conventional Fermi liquid, even if a superconducting order parameter appears or the multisite self-energy is anomalous. The electron liquid characterized by the single-site self-energy is a conventional Fermi liquid. The Fermi liquid is further stabilized by the resonating-valence-bond (RVB) mechanism. The stabilized Fermi liquid is a relevant unperturbed state that can be used to study superconductivity and anomalous Fermi-liquid behaviors. The so-called spin-fluctuation-mediated exchange interaction, which includes the superexchange interaction as a part, is the attractive interaction that binds dx2−y2-wave Cooper pairs. An analysis of the spin susceptibility implies that, because of the electron–phonon interaction, the imaginary part of the exchange interaction has a sharp peak or dip at ±ω*, where ω*\\simeqωph in the normal state and (1⁄2)εG\\lesssimω*\\lesssim(1⁄2)εG+ωph in the superconducting state, where ωph is the energy of relevant phonons and εG is the superconducting gap. If the imaginary part has a sharp peak or dip at ±ω*, then the dispersion relation of quasi-particles has kink structures near ±ω* above and below the chemical potential, the density of states has dip-and-hump structures near ±ω* outside the coherence peaks in the superconducting state, and the anisotropy of the gap deviates from the simple dx2−y2-wave anisotropy.抄録全体を表示PDF形式でダウンロード (3285K) -
Toshiya Inami, Noriki Terada, Hideaki Kitazawa, Osamu Sakai2009 年 78 巻 8 号 p. 084713
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありResonant magnetic x-ray diffraction experiments were carried out on the stacked triangular lattice antiferromagnet GdPd2Al3. The experiments revealed an expected initial collinear c-axis order at TN1 followed by an additional in-plane order at TN2, while at the same time we found that the ground state is a helically ordered state of a very long incommensurate period of approximately 700 Å. The distribution of K-domains was highly anisotropic, and the domain with the modulation vector normal to the surface of the crystal was ascendant. Low-field magnetization is discussed on the basis of the observed incommensurate magnetic structure.抄録全体を表示PDF形式でダウンロード (160K) -
Koun Shirai, Haruhiko Dekura, Akira Yanase2009 年 78 巻 8 号 p. 084714
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありRecently, it has been discovered that the semiconductor α-boron becomes metallic at high pressures and finally undergoes a superconducting transition at 160 GPa, without causing any phase transition. Before the superconducting transition, a step is often observed in the pressure dependence of electrical resistivity in this class of boron crystals, which possess icosahedron-based structures. This step structure used to be thought to occur due to a phase transitions. In the present paper, we show that the step of α-boron at 50 GPa is not due to a phase transition. It is caused by a gradual change in the bonding character from semiconductor to metal. The increase in the metallic character is caused by the shortening of the three-center bond, which is a characteristic feature of icosahedron-based boron crystals. This shortening of the three-center bond enhances the bonding character of the conduction bottom band and finally closes the band gap. However, even far before the gap closing, the shortening has important consequences for the crystal properties of α-boron: for the changes in the deformation of the lattice and in the librational phonon mode at approximately 50 GPa. This change in structure affects the change in band structure, that is, the bottom of the conduction band initially moves from the Γ point toward the Z point until p=50 GPa and then almost terminates in the middle point. The step in resistivity is a direct consequence of the change in this energy gap. This provides a coherent understanding of the characteristic changes in resistivity, the deformation of the lattice, and the librational mode.抄録全体を表示PDF形式でダウンロード (627K) -
Jun Sugiyama, Yutaka Ikedo, Oren Ofer, Martin Månsson, Eduardo J ...2009 年 78 巻 8 号 p. 084715
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありThe magnetic nature of the CaFe2O4-type NaMn2O4 and Li0.92Mn2O4, in which Mn ions form a zigzag chain along the b-axis, have been investigated by muon-spin rotation and relaxation (μ+SR) and susceptibility (χ) measurements in the temperature range between 1.9 and 250 K using polycrystalline samples. Weak transverse-field μ+SR measurements revealed the existence of a bulk antiferromagnetic (AF) transition for NaMn2O4 at TN=39 K and for Li0.92Mn2O4 at TN=44 K, although the χ(T) curve did not exhibit a clear anomaly around TN for either compound. Below TN, however, the zero-field μ+SR spectra in both samples did not show the oscillatory signal characteristic of long range magnetic order. Instead, a slowly relaxing tail is observed. Comparisons with the calculated internal magnetic field for the AF ordered phase suggests that the AF spin structure is disordered and/or rapidly fluctuating. In the paramagnetic region above 100 K, a nuclear magnetic field in Li0.92Mn2O4 was found to be dynamic, whereas that in NaMn2O4 was almost static. This implies the diffusive motion of Li+ ions in Li0.92Mn2O4 even below 250 K.抄録全体を表示PDF形式でダウンロード (1219K) -
Kazuo Hida, Ken’ichi Takano, Hidenori Suzuki2009 年 78 巻 8 号 p. 084716
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありWe formulate statistical mechanics for a mixed diamond chain with spins 1 and 1/2. Owing to a series of conservation laws, any eigenstate of this system is decomposed into eigenstates of finite odd-length spin-1 chains. The ground state undergoes five quantum phase transitions with varying λ, a parameter that controls frustration. We evaluated the residual entropy and Curie constant which characterize each phase and phase boundary at low temperatures. We further find various characteristic finite-temperature properties such as the nonmonotonic temperature dependence of magnetic susceptibility, the multipeak structure in the λ-dependence of entropy, the plateau-like temperature dependence of entropy and the multipeak structure of specific heat.抄録全体を表示PDF形式でダウンロード (473K) -
Hidekazu Mukuda, Nobuyuki Terasaki, Nobukatsu Tamura, Hiroaki Kinouchi ...2009 年 78 巻 8 号 p. 084717
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありWe report systematic 57Fe-NMR and 75As-NMR/NQR studies on an underdoped sample (Tc=20 K), an optimally doped sample (Tc=28 K), and an overdoped sample (Tc=22 K) of oxygen-deficient iron (Fe)-based oxypnictide superconductor LaFeAsO1−y. A microscopic phase separation between superconducting domains and magnetic domains is shown to take place in the underdoped sample, indicating a local inhomogeneity in association with the density distribution of oxygen deficiencies. As a result, 1⁄T1T in the normal state of the superconducting domain decreases significantly upon cooling at both the Fe and As sites regardless of the electron-doping level in LaFeAsO1−y. On the basis of this result, we claim that 1⁄T1T is not always enhanced by antiferromagnetic fluctuations close to an antiferromagnetic phase in the underdoped superconducting sample. This contrasts with the behavior in hole-doped Ba0.6K0.4Fe2As2 (Tc=38 K), which exhibits a significant increase in 1⁄T1T upon cooling. We remark that the crucial difference between the normal-state properties of LaFeAsO1−y and Ba0.6K0.4Fe2As2 originates from the fact that the relevant Fermi surface topologies are differently modified depending on whether electrons or holes are doped into the FeAs layers.抄録全体を表示PDF形式でダウンロード (605K) -
Masashige Matsumoto, Mikito Koga, Hiroaki Kusunose2009 年 78 巻 8 号 p. 084718
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありA single impurity problem is investigated for multiband s-wave superconductors with different sign order parameters (s±-wave superconductors) suggested in Fe-pnictide superconductors. Not only intraband but also interband scattering is considered at the impurity. The latter gives rise to impurity-induced local boundstates close to the impurity. We present an exact form of the energy of the local boundstates as a function of strength of the two types of impurity scattering. The essential role of the impurity is unchanged in finite number of impurities. The main conclusions for a single impurity problem help us understand effects of dense impurities in the s±-wave superconductors. Local density of states around the single impurity is also investigated. We suggest impurity site nuclear magnetic resonance as a suitable experiment to probe the local boundstates that is peculiar to the s±-wave state. We find that the s±-wave model is mapped to a chiral dx2−y2±idxy-wave, reflecting the unconventional nature of the sign reversing order parameter. For a quantum magnetic impurity, interband scattering destabilizes the Kondo singlet.抄録全体を表示PDF形式でダウンロード (763K) -
Mika Kano, Yoshimitsu Kohama, David Graf, Fedor Balakirev, Athena S. S ...2009 年 78 巻 8 号 p. 084719
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありThe temperature dependence of the upper critical magnetic field (Hc2) in a BaFe1.84Co0.16As2 single crystal was determined via resistivity, for the inter-plane (H⊥ab) and in-plane (H||ab) directions in pulsed and static magnetic fields of up to 60 T. Suppressing superconductivity in a pulsed magnetic field at 3He temperatures permits us to construct an Hc2–T phase diagram from quantitative Hc2(0) values and determine its behavior in low temperatures. Hc2(0) with H||ab [Hc2||(0)] and H⊥ab [Hc2⊥(0)] are ∼55 and ∼50 T respectively. These values are ∼1.2–1.4 times larger than the weak-coupling Pauli paramagnetic limit (Hp=1.84Tc), indicating that enhanced paramagnetic limiting is essential and this superconductor is unconventional. While Hc2||ab is saturated at low temperature, Hc2 with H⊥ab (Hc2⊥) exhibits almost linear temperature dependence towards T=0 K which results in reduced anisotropy of Hc2 in low temperature. The anisotropy of Hc2 was ∼3.4 near Tc, and decreases rapidly with lower temperatures reaching ∼1.1 at T=0.7 K.抄録全体を表示PDF形式でダウンロード (919K) -
Yukio Yasui, Kenji Sato, Yoshiaki Kobayashi, Masatoshi Sato2009 年 78 巻 8 号 p. 084720
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありSingle-crystal samples of LiCu2O2 with spin 1/2 Cu2+ chains of edge-sharing CuO4 square planes (ribbon chains), have been characterized by X-ray diffraction, thermogravimetric analysis, and magnetic measurements. Neither the atomic deficiency nor the mixing of Cu and Li atoms has been found, indicating that lattice defects conceived as an origin of the reported multiferroic behavior can be excluded. Observations of clear anomalies found in the temperature (T) dependence of the specific heat and neutron integrated intensities of the magnetic Bragg reflections have presented clear confirmations that the system exhibits successive magnetic transitions at TN1∼24.5 K and TN2∼22.8 K. The magnetization–magnetic field (H) curve indicates that no spin-flop transition exists, at least, up to H=5.5 T. On the bases of these data and the magnetic structures obtained by our group at temperatures T<TN2 and TN2<T<TN1, arguments on the multiferroic properties of the system are presented.抄録全体を表示PDF形式でダウンロード (612K) -
Yoshiaki Kobayashi, Kenji Sato, Yukio Yasui, Taketo Moyoshi, Masatoshi ...2009 年 78 巻 8 号 p. 084721
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありNeutron diffraction and 7Li-NMR have been applied to determine the three dimensional magnetic structures of the multiferroic system LiCu2O2, which has four chains (ribbon chains) of edge-sharing CuO4 square planes in a unit cell. First, we have confirmed that there are successive magnetic transitions at TN1=24.5 K and TN2=22.8 K. In the T region between TN1 and TN2, the quasi one-dimensional spins (S=1⁄2) of Cu2+ ions within a chain have a collinear and sinusoidally modulated structure with Cu-moments parallel to the c-axis and with the modulation vector along the b-axis. At T<TN2, an ellipsoidal helical spin structure with the incommensurate modulation has been found. We present detailed parameters, describing the modulation amplitudes, helical axis vectors as well as the relative phases of the modulations of four ribbon chains, which can well reproduce both the NMR and neutron results, in the two magnetically ordered phases. This finding of the rather precise magnetic structures enables us to discuss the relationship between the magnetic structure and the multiferroic nature of the present system in zero magnetic field, as presented in our companion paper (paper I), and open a way how to understand the reported electric polarization under the finite magnetic field.抄録全体を表示PDF形式でダウンロード (533K) -
Kazutaka Kudo, Naoyuki Okumura, Yoshiyuki Miyoshi, Terukazu Nishizaki, ...2009 年 78 巻 8 号 p. 084722
発行日: 2009/08/15
公開日: 2011/12/28
ジャーナル 認証ありWe have determined the precise T–p phase diagram of Pb-substituted Bi2Sr2CuO6+δ by using the hole concentration p estimated from the Hall coefficient, and found that the superconducting region of Pb-substituted Bi2Sr2CuO6+δ is rather narrow as compared with other Bi-based high-Tc cuprates. In Bi-based single-layer high-Tc cuprates, the width of the superconducting region becomes more narrow as the maximum Tc (Tc,max) gets smaller. This is different from other high-Tc superconductors, in which Tc⁄Tc,max is described by a universal function of p. Furthermore, we have found that the p dependence of the pseudogap formation temperature T* projects to zero at the critical point pcr∼0.205–0.21, which is outside the superconducting region of Pb-substituted Bi2Sr2CuO6+δ. Taking into account that pcr of high-Tc cuprates is commonly located around p∼0.19–0.21, it is concluded that whether pcr is inside or outside the superconducting region simply depends on the width of the superconducting region.抄録全体を表示PDF形式でダウンロード (358K)