Hole Binding around Ni Impurity in Cuprates (2009)
Tsutsui, K., Toyama, A., Tohyama, T., Maekawa, S.
We examine the influence of Ni impurity in cuprates on the distribution of hole carriers by performing numerically exact diagonalization calculations for a model consisting of Cu3d, Ni3d, and O2p...
Nuclear Quadrupole Resonance Frequency in Multi-Layered Cuprates (2009)
Mori, M., Shooshtary, N. Afzal, Tohyama, T., Maekawa, S.
The 63Cu nuclear quadrupole resonance (NQR) frequency, nu_q, in the multi-layered cuprates is calculated in the cluster model by the exact diagonalization method. The charge imbalance between the...
Kondo quantum dot coupled to ferromagnetic leads: Numerical renormalization group study (2009)
Schön, G., Martinek, J., Sindel, M., Borda, L., Bulla, R., König, J., ...
Tunneling Electroresistance in Ferroelectric Tunnel Junctions with a Composite Barrier (2009)
Zhuravlev, M. Ye., Wang, Y., Maekawa, S., Tsymbal, E. Y.
Tunneling electroresistance (TER) effect is the change in the electrical resistance of a ferroelectric tunnel junction (FTJ) associated with polarization reversal in the ferroelectric barrier layer....
Coupled Superconducting Phase and Ferromagnetic Order Parameter Dynamics (2009)
Petkovic, I., Aprili, M., Barnes, S. E., Beuneu, F., Maekawa, S.
Via a direct coupling between the magnetic order parameter and the singlet Josephson supercurrent, we detect spin-wave resonances, and their dispersion, in ferromagnetic Josephson junctions in which...
Role of Bound Magnon in Magnetic Domain Wall Motion (2009)
Kim, Tae-Suk, Ieda, J., Maekawa, S.
We report on a quantum description of the domain wall (DW) motion under a spin current. A bound magnon, which is the zero mode of DW, is found to play a dominant role in DW dynamics. The bound magnon...
Optical conductivity in the t-J-Holstein Model (2008)
Vidmar, L., Bonca, J., Maekawa, S.
Using recently developed numerical method we compute charge stiffness and optical conductivity of the t-J model coupled to optical phonons. Coherent hole motion is most strongly influenced by the...
Sign reversal of ac Josephson current in a ferromagnetic Josephson junction (2008)
Hikino, S., Mori, M., Takahashi, S., Maekawa, S.
The ac Josephson effect in a ferromagnetic Josephson junction, which is composed of two superconductors separated by a ferromagnetic metal (FM), is studied by a tunneling Hamiltonian and Green's...
Zhang, L., Fujita, T., Chen, F., Feng, D. L., Maekawa, S., Chen, M. W.
Raman spectra of polycrystalline NdFeAsO1-xFx (x=0.0, 0.1, 0.2) compound have been systematically investigated as functions of temperature and fluorine concentration. Scanning electron microscopic...
Coexistence of superconductivity and antiferromagnetism in self-doped bilayer t-t'-J model (2008)
Gan, J. Y., Mori, M., Lee, T. K., Maekawa, S.
A self-doped bilayer t-t'-J model of an electron- and a hole-doped planes is studied by the slave-boson mean-field theory. A hopping integral between the differently doped planes, which are generated...
Origin of spatial variation of pairing gap in Bi-based high-Tc cuprates (2008)
Mori, M., Khaliullin, G., Tohyama, T., Maekawa, S.
Recently, scanning tunneling microscopy on Bi-2212 cuprate superconductor has revealed a spatial variation of the energy gap that is directly correlated with a modulation of the apical oxygen...
FMR induced Josephson Current in a Superconductor/Ferromagnet/Superconductor Junction (2008)
Hikino, S., Mori, M., Takahashi, S., Maekawa, S.
We propose the phase dynamics induced by spin waves in a superconductor/ferromagnet/superconductor (SC/FM/SC) Josephson junction. The resistively shunted junction (RSJ) model, which describes the...
Comparison of the prognosis among different age groups in elderly patients with hip fracture (2008)
Hagino, T, Ochiai, S, Wako, M, Sato, E, Maekawa, S, Hamada, Y
Ishii, K., Hoesch, M., Inami, T., Kuzushita, K., Ohwada, K., Tsubota, M., ...
We report a Cu K-edge resonant inelastic x-ray scattering (RIXS) study of high-Tc cuprates. Momentum-resolved charge excitations in the CuO2 plane are examined from parent Mott insulators to...
Kondo quantum dot coupled to ferromagnetic leads: Numerical renormalization group study (2007)
Sindel, M., Borda, L., Martinek, J., Bulla, R., Koenig, J., Schoen, G., ...
We systematically study the influence of ferromagnetic leads on the Kondo resonance in a quantum dot tuned to the local moment regime. We employ Wilson's numerical renormalization group method,...
Numerical approach to low-doping regime of the t-J model (2007)
Bonca, J., Maekawa, S., Tohyama, T.
We develop an efficient numerical method for the description of a single-hole motion in the antiferromagnetic background. The method is free of finite-size effects and allows calculation of physical...
Ishii, K., Tsutsui, K., Tohyama, T., Inami, T., Mizuki, J., Murakami, Y., ...
Momentum dependent charge excitations of a two-leg ladder are investigated by resonant inelastic x-ray scattering of (La,Sr,Ca)14Cu24O41. In contrast to the case of a square lattice, momentum...
Gate-controlled spin-splitting in quantum dots with ferromagnetic leads in the Kondo regime (2007)
Martinek, J., Sindel, M., Borda, L., Barnas, J., Bulla, R., König, J., ...
Magnetic Impurity States and Ferromagnetic Interaction in Diluted Magnetic Semiconductors (2007)
Ichimura, M., Tanikawa, K., Takahashi, S., Baskaran, G., Maekawa, S.
The electronic structure of diluted magnetic semiconductors is studied, especially focusing on the hole character. The Haldane-Anderson model is extend to a magnetic impurity, and is analyzed in the...
Mori, M., Hikino, S., Takahashi, S., Maekawa, S.
We study the influence of magnetic scattering on the Josephson critical current, Ic, in a superconductor/ferromagnetic metal/superconductor (SFS) junction by a tunneling Hamiltonian approach. An...
Long-range ferromagnetic correlations between Anderson impurities in a semiconductor host (2006)
Bulut, N., Tanikawa, K., Takahashi, S., Maekawa, S.
We study the two-impurity Anderson model for a semiconductor host using the quantum Monte Carlo technique. We find that the impurity spins exhibit ferromagnetic correlations with a range which can be...
Spin Injection and Nonlocal Spin Transport in Magnetic Nanostructures (2006)
We theoretically study the nonlocal spin transport in a device consisting of a nonmagnetic metal (N) and ferromagnetic injector (F1) and detector (F2) electrodes connected to N. We solve the...
Room Temperature Reversible Spin Hall Effect (2006)
Kimura, T., Otani, Y., Sato, T., Takahashi, S., Maekawa, S.
Reversible spin Hall effect comprising the "direct" and "inverse" spin Hall effects was successfully detected at room temperature. This experimental demonstration proves the fundamental relations...
Nonlocal spin Hall effect and spin-orbit interaction in nonmagnetic metals (2006)
Spin Hall effect in a nonlocal spin-injection device is theoretically studied. Using a nonlocal spin-injection technique, a pure spin current is created in a nonmagnetic metal (N). The spin current...
Magnetic memory and current amplification devices using moving domain walls (2006)
Barnes, S. E., Ieda, J., Maekawa, S.
A moving magnetic domain wall produces an electromotive force (emf). It is therefore possible to read the state of a magnetic memory device via the emf it produces when subject to an interrogation...
Effect of Kondo resonance on optical third harmonic generation (2006)
Jafari, S. A., Tohyama, T., Maekawa, S.
We use the method of dynamical mean field thoery, to study the effect of Kondo resonance on optical third harmonic generation (THG) spectra of strongly correlated systems across the metal-insulator...
Takahashi, S., Yamashita, T., Maekawa, S.
The crossed Andreev reflection in a hybrid nanostructure consisting of a d-wave superconductor and two quantum wires is theoretically studied. When the (110) oriented surface of the superconductor is...
Dynamical mean field theory of optical third harmonic generation (2006)
Jafari, S. A., Tohyama, T., Maekawa, S.
We formulate the third harmonic generation (THG) within the dynamical mean field theory (DMFT) approximation of the Hubbard model. In the limit of large dimensions, where DMFT becomes exact, the...
Bulut, N., Matsueda, H., Tohyama, T., Maekawa, S.
The angle-resolved photoemission spectrum of the organic conductor TTF-TCNQ exhibits an unusual transfer of spectral weight over a wide energy range for temperatures 60K
Controllable pi junction with magnetic nanostructures (2006)
Yamashita, T., Takahashi, S., Maekawa, S.
We propose a novel Josephson device in which 0 and $\pi$ states are controlled by an electrical current. In this system, the $\pi$ state appears in a superconductor/normal metal/superconductor...
G. Cervone, S. Maekawa, R. P. Singh, M. Hayakawa, M. Kafatos, A. Shvets
Surface Latent Heat Flux (SLHF) is an atmospheric parameter proportional to the evaporation from the Earth's surface. SLHF has been found to exhibit an anomalous behavior in the epicentral region...
Cervone, G., Maekawa, S., Singh, R. P., Hayakawa, M., Kafatos, M., Shvets, A.
Surface Latent Heat Flux (SLHF) is an atmospheric parameter proportional to the evaporation from the Earth's surface. SLHF has been found to exhibit an anomalous behavior in the epicentral region...
Cervone, G., Maekawa, S., Singh, R. P., Hayakawa, M., Kafatos, M., Shvets, A.
Surface Latent Heat Flux (SLHF) is an atmospheric parameter proportional to the evaporation from the Earth's surface. SLHF has been found to exhibit an anomalous behavior in the epicentral region...
Maekawa, S., Horie, T., Yamauchi, T., Sawaya, T., Ishikawa, M., Hayakawa, M., ...
A superimposed epoch analysis has been undertaken, in order to find the correlation of the ionospheric perturbations with seismic activity. We take the wave path from the Japanese LF transmitter...
Maekawa, S., Horie, T., Yamauchi, T., Sawaya, T., Ishikawa, M., Hayakawa, M., ...
A superimposed epoch analysis has been undertaken, in order to find the correlation of the ionospheric perturbations with seismic activity. We take the wave path from the Japanese LF transmitter...
Theory of RIXS in strongly correlated electron systems: Mott gap excitations in cuprates (2005)
Tohyama, T., Tsutsui, K., Maekawa, S.
We theoretically examine the momentum dependence of resonant inelastic x-ray scattering (RIXS) spectrum for one-dimensional and two-dimensional cuprates based on the single-band Hubbard model with...
Mori, M., Tohyama, T., Maekawa, S.
We study doping dependence of interlayer hoppings, t_\perp, in multilayered cuprates with four or more CuO_2 planes in a unit cell. When the double occupancy is forbidden in the plane, an effective...
Low energy electronic states and triplet pairing in layered cobaltates (2005)
Khaliullin, G., Koshibae, W., Maekawa, S.
The structure of the low-energy electronic states in layered cobaltates is considered starting from the Mott insulating limit. We argue that the coherent part of the wave-functions and the...
Nonequilibrium Kondo effect in a quantum dot coupled to ferromagnetic leads (2005)
Utsumi, Y., Martinek, J., Schön, G., Imamura, H., Maekawa, S.
Strength of the d_{x^2-y^2} pairing in the two-leg Hubbard ladder (2005)
In the ground state of the doped two-leg Hubbard ladder there are power-law decaying d_{x^2-y^2}-type pairing correlations. It is important to know the strength and the temperature scale of these...
Nonlinear Optical Response of Spin Density Wave Insulators (2005)
Jafari, S. A., Tohyama, T., Maekawa, S.
We calculate the third order nonlinear optical response in the Hubbard model within the spin density wave (SDW) mean field ansatz in which the gap is due to onsite Coulomb repulsion. We obtain...
Superconducting pi qubit with three Josephson junctions (2005)
Yamashita, T., Takahashi, S., Maekawa, S.
We propose a new qubit consisting of a superconducting ring with two ordinary zero junctions and one ferromagnetic pi junction. In the system, two degenerate stable states appear in the phase space...
Exact diagonalization study of optical conductivity in two-dimensional Hubbard model (2005)
Tohyama, T., Inoue, Y., Tsutsui, K., Maekawa, S.
The optical conductivity \sigma(\omega) in the two-dimensional Hubbard model is examined by applying the exact diagonalization technique to small square clusters with periodic boundary conditions up...
Onodera, H., Tohyama, T., Tsutsui, K., Maekawa, S.
We propose angle-resolved two-photon photoemission spectroscopy (AR-2PPES) as a technique to detect the location of the bottom of the upper Hubbard band (UHB) in two-dimensional insulating cuprates....
Magnetic correlations in the Hubbard model on triangular and Kagome lattices (2005)
Bulut, N., Koshibae, W., Maekawa, S.
In order to study the magnetic properties of frustrated metallic systems, we present Quantum Monte Carlo data on the magnetic susceptibility of the Hubbard model on triangular and Kagome lattices. We...
Anomalies of LF signal during seismic activity in November–December 2004 (2005)
A. A. Rozhnoi, M. S. Solovieva, O. A. Molchanov, M. Hayakawa, S. Maekawa, P. F. Biagi
A signal transmitted by Japan Time Standard LF station (40 kHz, Fukushima prefecture) and recorded in Petropavlovsk-Kamchatski (Russia) is analyzed during a time interval from 1 July 2004 till...
Anomalies of LF signal during seismic activity in November?December 2004 (2005)
Rozhnoi, A. A., Solovieva, M. S., Molchanov, O. A., Hayakawa, M., Maekawa, S., Biagi, P. F.
A signal transmitted by Japan Time Standard LF station (40 kHz, Fukushima prefecture) and recorded in Petropavlovsk-Kamchatski (Russia) is analyzed during a time interval from 1 July 2004 till 24...
Anomalies of LF signal during seismic activity in November?December 2004 (2005)
Rozhnoi, A. A., Solovieva, M. S., Molchanov, O. A., Hayakawa, M., Maekawa, S., Biagi, P. F.
A signal transmitted by Japan Time Standard LF station (40 kHz, Fukushima prefecture) and recorded in Petropavlovsk-Kamchatski (Russia) is analyzed during a time interval from 1 July 2004 till 24...
Ishii, K., Tsutsui, K., Endoh, Y., Tohyama, T., Maekawa, S., Hoesch, M., ...
We report a resonant inelastic x-ray scattering (RIXS) study of charge excitations in the electron-doped high-Tc superconductor Nd1.85Ce0.15CuO4. The intraband and interband excitations across the...
Superconducting pi qubit with a ferromagnetic Josephson junction (2004)
Yamashita, T., Tanikawa, K., Takahashi, S., Maekawa, S.
Solid-state qubits have the potential for the large-scale integration and for the flexibility of layout for quantum computing. However, their short decoherence time due to the coupling to the...
Currents induced by domain wall motion in thin ferromagnetic wires (2004)
Historically the role of eddy currents in the motion of Bloch walls has been extensively studied. In contrast the direct interaction of currents with such a moving wall has received very little...
Current-spin coupling for ferromagnetic domain walls in fine wires (2004)
The coupling between a current and a domain wall is examined. In the presence of a finite current and the absence of a potential which breaks the translational symmetry, there is a perfect transfer...
Mott gap excitations in twin-free YBa2Cu3O7-d (Tc = 93 K) studied by RIXS (2004)
Ishii, K., Tsutsui, K., Endoh, Y., Tohyama, T., Kuzushita, K., Inami, T., ...
Mott gap excitations in the high-Tc superconductor of the optimal doped YBa2Cu3O7-d (Tc = 93 K) have been studied by the resonant inelastic x-ray scattering method. Anisotropic spectra in the...
We propose a mechanism for high critical temperature (T_c) in the coexistent phase of superconducting- (SC) and antiferromagnetic (AF) CuO_2 planes in multilayered cuprates. The Josephson coupling...
Excitonic effect on optical response in one-dimensional two-band Hubbard model (2004)
Matsueda, H., Tohyama, T., Maekawa, S.
Motivated by the gigantic nonlinear optical response in the halogen-bridged Ni-compounds, the underlying electronic states of the compounds are examined in the one-dimensional two-band Hubbard model,...
Gate-controlled spin-splitting in quantum dots with ferromagnetic leads in the Kondo regime (2004)
Martinek, J., Sindel, M., Borda, L., Barnas, J., Bulla, R., König, J., ...
The effect of a gate voltage ($V_g$) on the spin-splitting of an electronic level in a quantum dot (QD) attached to ferromagnetic leads is studied in the Kondo regime using a generalized numerical...
Ishii, K., Inami, T., Ohwada, K., Kuzushita, K., Mizuki, J., Murakami, Y., ...
Electronic excitations near the Fermi energy in the hole doped manganese oxides (La1-xSrxMnO3, x=0.2 and 0.4) have been elucidated by using the resonant inelastic x-ray scattering (RIXS) method. A...
Matsueda, H., Tohyama, T., Maekawa, S.
One-dimensional Mott insulators exhibit giant nonlinear optical response. Based on the dynamical density matrix renormalization group method, photoexcited states and optical response in the...
Crossed Andreev reflection in a d-wave superconductor with two quantum point contacts (2004)
Takahashi, S., Yamashita, T., Maekawa, S.
We theoretically study the crossed Andreev reflection in a hybrid nanostructure which comprises a d-wave superconductor and two normal-metal quantum wires. When the superconductor of the (110)...
A. V. Shvets, M. Hayakawa, S. Maekawa
Results of simultaneous LF subionospheric monitoring over two different propagation paths prior to the very strong Tokachi earthquake (near the east coast of Hokkaido Island, 25 September 2003) of...
Physics of Transition Metal Oxides (2004)
Maekawa, S., Tohyama, T., Barnes, S. E., Ishihara, S., Koshibae, W., Khaliullin, G.
Many-body effects in nanospintronics devices (2004)
Utsumi, Y., Martinek, J., Bruno, P., Barnas, J., Maekawa, S.
Shvets, A. V., Hayakawa, M., Maekawa, S.
Results of simultaneous LF subionospheric monitoring over two different propagation paths prior to the very strong Tokachi earthquake (near the east coast of Hokkaido Island, 25 September 2003) of...
Shvets, A. V., Hayakawa, M., Maekawa, S.
Results of simultaneous LF subionospheric monitoring over two different propagation paths prior to the very strong Tokachi earthquake (near the east coast of Hokkaido Island, 25 September 2003) of...
Cortical selective vulnerability in motor neuron disease: a morphometric study (2004)
Maekawa, S., Al-Sarraj, S., Kibble, M., Landau, S., Parnavelas, J., Cotter, D., ...
Neuroimaging and neuropsychological studies have revealed that the primary motor cortex (PMC) and the extramotor cortical areas are functionally abnormal in motor neuron disease (MND, amyotrophic...
Cortical selective vulnerability in motor neuron disease: a morphometric study (2004)
Maekawa, S., Al-Sarraj, S., Kibble, M., Landau, S., Parnavelas, J., Cotter, D., ...
Neuroimaging and neuropsychological studies have revealed that the primary motor cortex (PMC) and the extramotor cortical areas are functionally abnormal in motor neuron disease (MND, amyotrophic...
Cortical selective vulnerability in motor neuron disease: a morphometric study (2004)
Maekawa, S., Al-Sarraj, S., Kibble, M., Landau, S., Parnavelas, J., Cotter, D., ...
Neuroimaging and neuropsychological studies have revealed that the primary motor cortex (PMC) and the extramotor cortical areas are functionally abnormal in motor neuron disease (MND, amyotrophic...
Temperature and Dimensionality Dependences of Optical Absorption Spectra in Mott Insulators (2003)
Onodera, H., Tohyama, T., Maekawa, S.
We investigate the temperature dependence of optical absorption spectra of one-dimensional (1D) and two-dimensional (2D) Mott insulators by using an effective model in the strong-coupling limit of a...
Current-driven domain wall motion in thin ferromagnetic wires (2003)
The coupling between a current and a Bloch wall is examined in the half-metal limit of the double exchange model. The conduction electrons transfer angular momentum to the Bloch wall with 100%...
Friedel oscillations in a two-band Hubbard model for CuO chains (2003)
Mori, M., Tohyama, T., Maekawa, S., Riera, J. A.
Friedel oscillations induced by open boundary conditions in a two-band Hubbard model for CuO chains are numerically studied. We find that for physically realistic parameters and close to quarter...
Spin Dependent Transport in Magnetic Nanostructures (2003)
Recent progress in physics on spin dependent transport in magnetic nanostructures is reviewed. Special attention is paid on the spin accumulation and spin current caused by spin injection into...
Kagom\'e in triangular lattice: electronic state of CoO_2 layer with hexagonal structure (2003)
The electronic state in layered cobalt oxides with hexagonal structure is examined. We find that the electronic structure reflects the nature of the Kagom\'e lattice hidden in the CoO_2 layer which...
Mott Gap Excitations and Resonant Inelastic X-Ray Scattering in Doped Cuprates (2003)
Tsutsui, K., Tohyama, T., Maekawa, S.
Predictions are made for the momentum- and carrier-dependent degradation of the Mott gap upon doping in high-Tc cuprates as would be observed in Cu K-edge resonant inelastic x-ray scattering (RIXS)....
Kondo effect in quantum dots coupled to ferromagnetic leads (2003)
Martinek, J., Utsumi, Y., Imamura, H., Barnas, J., Maekawa, S., König, J., ...
Nonequilibrium spin fluctuations in nonmagnetic single-electron transistors and quantum dots. (2003)
Martinek, J., Barnas, J., Schön, G., Takahashi, S., Maekawa, S.
Journal of Superconductivity, 16(2003), 2, S. 343-346
Spin Injection and Detection in Magnetic Nanostructures (2002)
We study theoretically the spin transport in a nonmagnetic metal connected to ferromagnetic injector and detector electrodes. We derive a general expression for the spin accumulation signal which...
We examine the thermodynamic properties of the hole- and electron-doped cuprates by using the t-t'-t''-J model. We find that the chemical potential shows different doping dependence between the hole...
Tohyama, T., Maekawa, S., Prelovsek, P.
We examine the thermodynamic and thermoelectric properties in the stripe phase of high-Tc cuprates, by using the finite-temperature Lanczos technique for the t-J model with a potential that...
Kondo effect in quantum dots coupled to ferromagnetic leads (2002)
Martinek, J., Utsumi, Y., Imamura, H., Barnas, J., Maekawa, S., König, J., ...
We study the Kondo effect in a quantum dot which is coupled to ferromagnetic leads and analyse its properties as a function of the spin polarization of the leads. Based on a scaling approach we...
Tohyama, T., Onodera, H., Tsutsui, K., Maekawa, S.
We investigate the resonant two-magnon Raman scattering in two-dimensional (2D) Mott insulators by using a half-filled 2D Hubbard model in the strong coupling limit. By performing numerical...
Spin accumulation and cotunneling effects in ferromagnetic single-electron transistors. (2002)
Martinek, J., Barnas, J., Maekawa, S., Schoeller, H., Schön, G.
Proc.of the 4th Internat.Symp.on Metallic Multilayers (MML'01), Aachen, June 24-29, 2001
Spin accumulation in ferromagnetic single-electron transistors in the cotunneling regime. (2002)
Martinek, J., Barnas, J., Maekawa, S., Schoeller, H., Schön, G.
Physical Review B, 66(2002) S.014402/1-5
Zone Edge Softening and Relaxation in the Double Exchange Model (2001)
The $J\to \infty$ double exchange model is formulated in terms of three auxiliary particles. A slow true bosonic magnon propagates by admixture with a fast fermionic pseudo-magnon. This process...
Magnetic Ordering, Orbital Ordering and Resonant X-ray Scattering in Perovskite Titanates (2001)
Ishihara, S., Hatakeyama, T., Maekawa, S.
The effective Hamiltonian for perovskite titanates is derived by taking into account the three-fold degeneracy of $t_{2g}$ orbitals and the strong electron-electron interactions. The magnetic and...
Bi-layer splitting in overdoped high $T_{c}$ cuprates (2001)
Recent angle-resolved photoemission data for overdoped Bi2212 are explained. Of the peak-dip-hump structure, the peak corresponds the $\vec q =0$ component of a hole condensate which appears at...
A Jordan-Wigner transformation for the $t-J$ and Hubbard models with holes (2001)
A Jordan-Wigner (JW) transformation for the $t-J$ and Hubbard models is described. Introduced are holon and doublon particles for hole and double occupied sites. There is only a single spin sector...
Inami, T., Ishihara, S., Kondo, H., Mizuki, J., Fukuda, T., Maekawa, S., ...
We report resonant inelastic x-ray scattering experiments of the orbital ordered manganite LaMnO3. When the incident photon energy is tuned near the Mn K absorption edge, the spectra reveal three...
Spin transport and relaxation in superconductors (2001)
Yamashita, T., Takahashi, S., Imamura, H., Maekawa, S.
We study theoretically the effect of spin relaxation on the spin transport in a ferromagnet/superconductor(FM/SC) tunnel junction. When spin-polarized electrons are injected into the SC from the FM,...
Theory of Raman Scattering from Orbital Excitations in Manganese Oxides (2001)
Okamoto, S., Ishihara, S., Maekawa, S.
We present a theory of the Raman scattering from the orbital wave excitations in manganese oxides. Two excitation processes of the Raman scattering are proposed. The Raman scattering cross section is...
Electronic States in the Antiferromagnetic Phase of Electron-Doped High-Tc Cuprates (2001)
We investigate the electronic states in the antiferromagnetic (AF) phase of electron-doped cuprates by using numerically exact diagonalization technique for a t-t'-t''-J model. When AF correlation...
Hirota, K., Ishihara, S., Fujioka, H., Kubota, M., Yoshizawa, H., Moritomo, Y., ...
Low-temperature spin dynamics of the double-layered perovskite La_2-2x_Sr_1+2x_Mn_2_O_7 (LSMO327) was systematically studied in a wide hole concentration range (0.3
Electronic Structure of Mott Insulators Studied by Inelastic X-ray Scattering (2001)
Hasan, M. Z., Isaacs, E. D., Shen, Z-X., Miller, L. L., Tsutsui, K., Tohyama, T., ...
The electronic structure of Mott insulators continues to be a major unsolved problem in physics despite more than half-century of intense research efforts. Well-developed momentum-resolved...
Vanishing Hall Constant in the Stripe Phase of Cuprates (2001)
Prelovsek, P., Tohyama, T., Maekawa, S.
The Hall constant R_H is considered for the stripe structures. In order to explain the vanishing of R_H in LNSCO at x = 1/8, we use the relation of R_H to the Drude weight D as well as direct...
Resonant Inelastic X-ray Scattering from Charge and Orbital Excitations in Manganites (2000)
Kondo, H., Ishihara, S., Maekawa, S.
We present a theory of the resonant inelastic x-ray scattering (RIXS) to study electronic excitations in orbital ordered manganites. The charge and orbital excitations of the Mn 3d electron are...
Effect of nonmagnetic impurities on stripes in high-Tc cuprates (2000)
Tohyama, T., Takahashi, M., Maekawa, S.
We perform the numerically exact diagonalization study of the t-J model with nonmagnetic impurities to clarify the relation between Zn impurities and the stripes. By examining the hole-hole...
Shibata, Y., Tohyama, T., Maekawa, S.
We examine the temperature dependence of the electronic states in the stripe phase of high-Tc cuprates by using the t-J model with a potential that stabilizes vertical charge stripes. Charge and...
Joule heating generated by spin current through Josephson junctions (2000)
Takahashi, S., Yamashita, T., Koyama, T., Maekawa, S., Imamura, H.
We theoretically study the spin-polarized current flowing through a Josephson junction (JJ) in a spin injection device. When the spin-polarized current is injected from a ferromagnet (FM) in a...
Orbital liquid in three dimensional Mott insulator: $LaTiO_3$ (2000)
We present a theory of spin and orbital states in Mott insulator $LaTiO_3$. The spin-orbital superexchange interaction between $d^1(t_{2g})$ ions in cubic crystal suffers from a pathological...
Antiferromagnetic ordering of S=1/2 triangles in La4Cu3MoO12 (2000)
Azuma, M, Odaka, T, Takano, M, Vander Griend, DA, Poeppelmeier, KR, Narumi, Y, ...
Nonlinear optical response and spin-charge separation in one-dimensional Mott insulators (2000)
Mizuno, Y., Tsutsui, K., Tohyama, T., Maekawa, S.
We theoretically study the nonlinear optical response and photoexcited states of the Mott insulators. The nonlinear optical susceptibility \chi^(3) is calculated by using the exact diagonalization...
Angle-resolved photoemission in high Tc cuprates from theoretical viewpoints (2000)
The angle-resolved photoemission (ARPES) technique has been developed rapidly over the last decay, accompanied by the improvement of energy and momentum resolutions. This technique has been...
Okamoto, S., Ishihara, S., Maekawa, S.
Correlation between orbital structure and magnetic ordering in bilayered manganites is examined. A level separation between the $3d_{3z^2-r^2}$ and $3d_{x^2-y^2}$ orbitals in a Mn ion is calculated...
Resonant inelastic x-ray scattering in one-dimensional copper oxides (1999)
Tsutsui, K., Tohyama, T., Maekawa, S.
The Cu K-edge resonant inelastic x-ray scattering (RIXS) spectrum in one-dimensional insulating cuprates is theoretically examined by using the exact diagonalization technique for the extended...
Phase Transition in Perovskite Manganites with Orbital Degree of Freedom (1999)
Okamoto, S., Ishihara, S., Maekawa, S.
Roles of orbital degree of freedom of Mn ions in phase transition as a function of temperature and hole concentration in perovskite manganites are studied. It is shown that the orbital order-disorder...
Momentum Dependence of Resonant Inelastic X-Ray Scattering Spectrum in Insulating Cuprates (1999)
Tsutsui, K., Tohyama, T., Maekawa, S.
The resonant inelastic x-ray scattering spectrum in insulating cuprates is examined by using the exact diagonalization technique on small clusters in the two-dimensional Hubbard model with second and...
Interchain interactions and magnetic properties of Li2CuO2 (1999)
Mizuno, Y., Tohyama, T., Maekawa, S.
An effective Hamiltonian is constructed for an insulating cuprate with edge-sharing chains Li2CuO2.The Hamiltonian contains the nearest and next-nearest neighboring intrachain and zigzag-type...
Effect of Coulomb blockade on STM current through a granular film (1999)
Imamura, H., Chiba, J., Mitani, S., Takanashi, K., Takahashi, S., Maekawa, S., ...
The electron transport through an array of tunnel junctions consisting of an STM tip and a granular film is studied both theoretically and experimentally. When the tunnel resistance between the tip...
Spin Liquid State around a Doped Hole in Insulating Cuprates (1999)
Tohyama, T., Shibata, Y., Maekawa, S., Nagaosa, N., Miller, L. L.
The numerically exact diagonalization study on small clusters of the t-J model with the second- and third- neighbor hopping terms shows that a novel spin liquid state is realized around a doped hole...
Okamoto, S., Ishihara, S., Maekawa, S.
The spin and orbital phase diagram for perovskite manganites are investigated as a function of temperature and hole concentration. The superexchange and double exchange interactions dominate the...
Takahashi, S., Imamura, H., Maekawa, S.
We theoretically study the spin-dependent transport in a ferromagnet/super- conductor/ferromagnet double tunnel junction. The tunneling current in the antiferromagnetic alignment of the...
Difference of optical conductivity between one- and two-dimensional doped nickelates (1999)
Tsutsui, K., Koshibae, W., Maekawa, S.
We study the optical conductivity in doped nickelates, and find the dramatic difference of the spectrum in the gap ($\omega$$\alt$4 eV) between one- (1D) and two-dimensional (2D) nickelates. The...
Effect of Stripes on Electronic States in Underdoped La_{2-x}Sr_xCuO_4 (1999)
Tohyama, T., Nagai, S., Shibata, Y., Maekawa, S.
We investigate the electronic states of underdoped La_{2-x}Sr_xCuO_4 (LSCO) by using a microscopic model, i.e., t-t'-t''-J model, containing vertical charge stripes. The numerically exact...
Field Induced Transition from Metal to Insulator in the CMR Manganites (1998)
Endoh, Y., Nojiri, H., Kaneko, K., Hirota, K., Fukuda, T., Kimura, H., ...
The gigantic reduction of the electric resistivity under the applied magnetic field, CMR effect, is now widely accepted to appear in the vicinity of the insulator to metal transition of the...
Maekawa, S., Ishihara, S., Okamoto, S.
A systematic study of the electronic structure in perovskite manganites is presented. The effective Hamiltonian is derived by taking into account the degeneracy of $e_g$ orbitals and strong electron...
Effect of magnetic frustration on single-hole spectral function in the t-t'-t''-J model (1998)
Shibata, Y., Tohyama, T., Maekawa, S.
We examine the effect of the magnetic frustration J' on the single-hole spectral function in the t-t'-t''-J model. At zero temperature, the exact diagonalization (ED) and the self-consistent Born...
Stripe Stability in the Extended t-J Model on Planes and Four-Leg Ladders (1998)
Tohyama, T., Gazza, C., Shih, C. T., Chen, Y. C., Lee, T. K., Maekawa, S., ...
The tendencies to phase-separation and stripe formation of the t-J model on planes and four-leg ladders have been here reexamined including hole hopping terms t', t'' beyond nearest-neighbor sites....
Electronic and magnetic states in doped LaCoO_3 (1998)
Tsutsui, K., Inoue, J., Maekawa, S.
The electronic and magnetic states in doped perovskite cobaltites, (La, Sr)CoO_3, are studied in the numerically exact diagonalization method on Co_2O_{11} clusters. For realistic parameter values,...
Kobayashi, K., Mizokawa, T., Fujimori, A., Isobe, M., Ueda, Y., Tohyama, T., ...
We have made an angle-resolved photoemission study of a one-dimensional (1D) Mott-Hubbard insulator Na_{0.96}V_{2}O_{5} and found that the spectra of the V 3d lower Hubbard band are strongly...
Insulator-Metal Transition in One Dimension Induced by Long-Range Electronic Interactions (1997)
Poilblanc, D., Yunoki, S., Maekawa, S., Dagotto, E.
The effects of a long range electronic potential on a one dimensional commensurate Charge Density Wave (CDW) state are investigated. Using numerical techniques it is shown that a transition to a...
Theory of tunneling magnetoresistance in granular magnetic films (1996)
A mechanism for the large magnetoresistance observed recently in Co-Al-O granular magnetic films is presented. It is shown that the resistivity decreases with increasing applied magnetic field...
Heavy Quasiparticles in the Anderson Lattice Model (1995)
Tsutsui, K., Ohta, Y., Eder, R., Maekawa, S., Dagotto, E., Riera, J.
An exact-diagonalization technique on small clusters is used to study the dynamics of the one-dimensional symmetric Anderson lattice model. Our calculated excitation spectra reproduce key features...
Excitation Spectra of the Negative-U Hubbard Model: A Small-Cluster Study (1995)
Ohta, Y., Nakauchi, A., Eder, R., Tsutsui, K., Maekawa, S.
An exact-diagonalization technique on small clusters is used to study low-lying excitations and superconductivity in the two-dimensional negative-$U$ Hubbard model. We first calculate the...
Ground state properties and dynamics of the bilayer t-J model (1995)
Eder, R., Ohta, Y., Maekawa, S.
We present an exact diagonalization study of bilayer clusters of t-J model. Our results indicate a crossover between two markedly different regimes which occurs when the ratio J_perp/J between...
Anomalous Spin and Charge Dynamics of the 2D t-J Model at low doping (1995)
Eder, R., Ohta, Y., Maekawa, S.
We present an exact diagonalization study of the dynamical spin and density correlation function of the 2D t-J model for hole doping < 25%. Both correlation functions show a remarkably regular, but...
Bogoliubov Quasiparticle Excitations in the Two-Dimensional t-J Model (1994)
Ohta, Y., Shimozato, T., Eder, R., Maekawa, S.
Using a proposed numerical technique for calculating anomalous Green's functions characteristic of superconductivity, we show that the low-lying excitations in a wide parameter and doping region of...
Gutzwiller wavefunction in the three-band Hubbard model: A variational Monte Carlo study (1993)
Oguri, A., Asahta, T., Maekawa, S.
The Gutzwiller wave function for the three-band Hubbard model on a two dimensional CuO$_2$ plane is studied by using the variational Monte Carlo (VMC) method in the limit $U_d \to \infty$, where...
UPPER CRITICAL FIELDS IN RARE EARTH COMPOUNDS (1978)
Maekawa, S., Tachiki, M., Kurita, H.
The upper critical fields Hc2 in the rare earth superconductors are obtained in the dirty limit as functions of the intra- and interatomic exchange interactions and the concentration of the magnetic...
UPPER CRITICAL FIELDS IN RARE EARTH COMPOUNDS (1978)
Maekawa, S., Tachiki, M., Kurita, H.
The upper critical fields Hc2 in the rare earth superconductors are obtained in the dirty limit as functions of the intra- and interatomic exchange interactions and the concentration of the magnetic...
UPPER CRITICAL FIELDS IN RARE EARTH COMPOUNDS (1978)
Maekawa, S., Tachiki, M., Kurita, H.
The upper critical fields Hc2 in the rare earth superconductors are obtained in the dirty limit as functions of the intra- and interatomic exchange interactions and the concentration of the magnetic...
Electron Microscopic and Diffraction Study of Silicon Oxide Film (1961)
SUGATA, E., YOKOYA, H., MAEKAWA, S., EDAGAWA, H., MORITA, Y.
Maekawa, S, Fukuda, K, Yamauchi, T, Yamaguchi, T, Takahashi, K, Sugawa, K
A total of 124 normal school children in three classes (aged 8 to 9) were examined for beta-hemolytic streptococci for 29 months from August 1977 to December 1979 be means of serial monthly throat...
Maekawa, S, De Szalay, C, Ovary, Z
Anti-2,4-dinitrophenyl (DNP) IgE producing hybridoma B 53 when injected subcutaneously is established equally well in syngeneic BALB/c (heavy-chain allotype a) and congenic CB20 (heavy-chain allotype...
Studies on the interaction between actin and cofilin purified by a new method.
Yonezawa, N, Nishida, E, Maekawa, S, Sakai, H
Cofilin is a 21,000-Mr actin-binding protein that widely exists in mammalian tissues. (1) A new purification procedure for porcine brain cofilin has been developed that involves (NH4)2SO4...
Maekawa, S, Fukuda, K, Yamauchi, T, Yamaguchi, T, Takahashi, K, Sugawa, K
A total of 124 normal school children in three classes (aged 8 to 9) were examined for beta-hemolytic streptococci for 29 months from August 1977 to December 1979 be means of serial monthly throat...
Maekawa, S, De Szalay, C, Ovary, Z
Anti-2,4-dinitrophenyl (DNP) IgE producing hybridoma B 53 when injected subcutaneously is established equally well in syngeneic BALB/c (heavy-chain allotype a) and congenic CB20 (heavy-chain allotype...
Studies on the interaction between actin and cofilin purified by a new method.
Yonezawa, N, Nishida, E, Maekawa, S, Sakai, H
Cofilin is a 21,000-Mr actin-binding protein that widely exists in mammalian tissues. (1) A new purification procedure for porcine brain cofilin has been developed that involves (NH4)2SO4...