A5050320369- Physics of Superconductivity and Magnetism
- Advanced Condensed Matter Physics
- Theoretical and Computational Physics
- Quantum many-body systems
- Magnetism in coordination complexes
- Quantum and electron transport phenomena
- Laser-Matter Interactions and Applications
- Topological Materials and Phenomena
- Organic and Molecular Conductors Research
- Magnetic properties of thin films
- Magnetic and transport properties of perovskites and related materials
- Advanced Fiber Laser Technologies
- Cold Atom Physics and Bose-Einstein Condensates
- Semiconductor Quantum Structures and Devices
- Advanced Chemical Physics Studies
- Atomic and Molecular Physics
- Laser-Plasma Interactions and Diagnostics
- Spacecraft and Cryogenic Technologies
- Rare-earth and actinide compounds
- Photonic and Optical Devices
- Semiconductor materials and devices
- Algebraic structures and combinatorial models
- Advanced NMR Techniques and Applications
- Planetary Science and Exploration
- Photonic Crystals and Applications
University of Hyogo
2014-2025
Kyoto Institute of Technology
2023
Okayama University of Science
2015
Japan Atomic Energy Agency
2014
SPring-8
2014
Osaka Prefecture University
2013
NTT Basic Research Laboratories
1996-2011
Fuji Electric (Japan)
2007-2011
Kyoto University
2007
NTT (United States)
2002-2006
Tight-binding electrons on the honeycomb lattice are studied where nearest-neighbor hoppings in three directions ${t}_{a}$, ${t}_{b}$, and ${t}_{c}$, respectively. For isotropic case---namely, for ${t}_{a}={t}_{b}={t}_{c}$---two zero modes exist energy dispersions at vanishing points linear momentum $k$. Positions of move space as ${t}_{c}$ varied. It is shown that if...
We study the system size dependence of singlet-triplet excitation gap in $S=1/2$ kagome-lattice Heisenberg antiferromagnet by numerical diagonalization. successfully obtain a new result cluster 42 sites. The two sequences gaps systems with even-number sites and that odd-number are separately analyzed. Careful examination clarifies there is no contradiction when we consider to be gapless.
We investigate the $S=1/2$ quantum spin antiferromagnets on triangular and Kagome lattices in magnetic field, using numerical exact diagonalization. Particularly we focus an anomalous magnetization behavior of each system at 1/3 saturation magnetization. The critical exponent analyses suggest that it is a conventional plateau lattice, while unconventional phenomenon, called ramp, lattice.
Experimental quest for the hypothetical "quantum spin liquid" state has recently met a few promising candidate materials including organic salts \kappa-(ET)2Cu2(CN)3 and EtMe3Sb[Pd(dmit)2]2, S=1/2 triangular-lattice Heisenberg antiferromagnets consisting of molecular dimers. These compounds exhibit no magnetic ordering nor freezing down to very low temperature, while various physical quantities gapless behaviors. Recent dielectric measurements revealed glassy response suggesting random...
We have succeeded in synthesizing single crystals of a new organic radical 3-Cl-4-F-V [3-(3-chloro-4-fluorophenyl)-1,5-diphenylverdazyl]. Through the ab initio molecular orbital calculation and analysis magnetic properties, this compound was confirmed to be first experimental realization an S=1/2 spin-ladder system with ferromagnetic leg interactions. The field-temperature phase diagram indicated that ground state is situated very close quantum critical point. Furthermore, we found...
Using the numerical diagonalization method, we study \(S=1/2\) Heisenberg antiferromagnet on a two-dimensional lattice composed of vertex-sharing triangles that call shuriken lattice. This is similar to kagome but with slight difference. We examine ground-state properties and magnetization process this model. find jump appears at higher-field-side edge plateau one-third height saturation. A spin-flop phenomenon clearly observed even when system isotropic in spin space.
We report the results of magnetization and specific heat measurements on Ba 3 NiSb 2 O 9 , which is a quasi-two-dimensional spin-1 triangular-lattice antiferromagnet. observed nonclassical plateau at one-third saturation that driven by spin frustration quantum fluctuation. Exact diagonalization for 21-site rhombic cluster was performed to analyze process. Experimental calculated agree well.
The magnetization process of the S=1/2 Heisenberg antiferromagnet on kagome lattice is studied by numerical-diagonalization method. We successfully obtain a new result 42-site cluster in entire range. Our analysis clarifies that critical behavior around one-third height saturation different from typical well-known plateau two-dimensional systems. also examine effect $\sqrt{3}\times\sqrt{3}$-type distortion added to lattice. find at undistorted point just boundary between two phases show...
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTApproach to a Single-Component Ferrimagnetism by Organic Radical CrystalsYuko Hosokoshi, Keiichi Katoh, Yasuhiro Nakazawa, Hiroki Nakano, and Katsuya InoueView Author Information Institute for Molecular Science Nishigonaka 38 Myodaiji Okazaki 444-8585, Japan Research Center Thermodynamics Faculity of Science, Osaka University Machikaneyama 1-1 Toyonaka-city, 560-0043 Osaka, Department Applied Physics, The Tokyo Hongo 7-3-1, Bunkyo-ku,...
We study the S=1/2 Heisenberg antiferromagnet on Cairo pentagon lattice by numerical-diagonalization method. tune ratio of two antiferromagnetic interactions coming from kinds inequivalent sites in this lattice, examining magnetization process antiferromagnet; particular attention is given to one-third height saturation. find that quantum phase transition occurs at a specific and plateau appears vicinity transition. The accompanied jump one side among edges due spin-flop phenomenon. Which...
Susceptibility and high field magnetization measurements have been performed on powder samples of an $S$=1 bond alternating chain compound [\{Ni(333-tet)($\mu$-N$_3$)\}$_n$](ClO$_4$)$_n$ (333-tet=tetraamine N,N'-bis(3-aminopropyl)-1,3-propanediamine). As the temperature is decreased, susceptibility exhibits a round maximum at around 120 K decreases gradually down to 10 K, then falls rapidly with logarithmic curvature which behavior gapless or nearly antiferromagnetic chain. Magnetization up...
Stable organic biradical crystals PNNNO, ${\mathrm{F}}_{2}\mathrm{PNNNO},$ and PIMNO of the PNNNO family were synthesized. ${\mathrm{PNNNO}=2\ensuremath{-}[{4}^{\ensuremath{'}}\ensuremath{-}$...
A simple and flexible method is presented for generating a partially coherent light which obtains the highly smooth focused beam pattern. The divergence of 32 times diffraction limited having spectral width 1.6 nm has been easily reproducibly achieved by injecting laser pulse from an actively mode-locked Nd:YLF oscillator to single mode optical fiber, coupled multimode fiber. Temporal evolution smoothing due induced incoherency was examined with temporally resolved measurements through...
We present a detailed investigation into the optical characteristics of individual InAs quantum dots (QDs) grown by metalorganic chemical vapor deposition, with low temperature emission in telecoms window around $1300\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$. Using microphotoluminescence (PL) spectroscopy we have identified neutral, positively charged, and negatively charged exciton biexciton states. Temperature-dependent measurements reveal dot-charging effects due to differences carrier...
This paper describes the next generation 1200 V trench-gate FS-IGBT chip technologies based on concepts of "low noise" and power dissipation". The novel design IGBT surface structure has been able to realize 36% reduction turn-on dissipation when compared conventional IGBTs under operating condition set same FWD reverse recovery dv/dt. Furthermore, trade-off relationship between on-state voltage turn-off improved about 20% without oscillation even in extreme condition.
We propose two methods of estimating a systematic error in extrapolation to the infinite-size limit study measuring Haldane gaps one-dimensional Heisenberg antiferromagnet with integer spin up S =5. The finite-size obtained by numerical diagonalizations based on Lanczos algorithm are presented for sizes that have not previously been reported. changes boundary conditions also examined. successfully demonstrate our work well. gap =1 is estimated be 0.4104789 ±0.0000013. obtain =5, which make...
We study ferrimagnetism in the ground state of antiferromagnetic Heisenberg model on spatially anisotropic kagome lattice, which conventional Lieb–Mattis type appears region weak frustration whereas is nonmagnetic isotropic case. Numerical diagonalizations small finite-size clusters are carried out to examine spontaneous magnetization. find that magnetization changes continuously intermediate between and phase. Local shows strong dependence site position, suggests non-Lieb–Mattis ferrimagnetism.
We study the S = 1 Heisenberg antiferromagnet on a spatially anisotropic triangular lattice by numerical diagonalization method.We examine stability of long-range order three-sublattice structure observed in isotropic system between case and isolated one-dimensional chains.It is found that long-range-ordered ground state with this exists range 0.7 < ∼ J2/J1 ≤ 1, where J1 interaction amplitude along chains J2 other interactions.
A modified spin-wave theory is applied to the one- and two-dimensional quantum Heisenberg model with long-range ferromagnetic interactions proportional ${\mathit{r}}^{\mathrm{\ensuremath{-}}\mathit{p}}$[scrH=-1/2${\mathit{tsum}}_{\mathit{i}\mathrm{\ensuremath{\ne}}\mathit{j}}$ (${\mathit{J}}_{0}$/${\mathit{r}}_{\mathit{i}\mathit{j}}^{\mathit{p}}$)${\mathbf{S}}_{\mathit{i}}$\ensuremath{\cdot}${\mathbf{S}}_{\mathit{j}}$]. It shown that for dp2d there exists a phase transition at finite...