A5005752643- Iron-based superconductors research
- Physics of Superconductivity and Magnetism
- Magnetic and transport properties of perovskites and related materials
- Rare-earth and actinide compounds
- Advanced Condensed Matter Physics
- Machine Learning in Materials Science
- Inorganic Chemistry and Materials
- Electronic and Structural Properties of Oxides
- Dynamics and Control of Mechanical Systems
- Superconductivity in MgB2 and Alloys
- 2D Materials and Applications
- Advanced Thermoelectric Materials and Devices
- Fluid Dynamics Simulations and Interactions
- Vibration and Dynamic Analysis
- Gaze Tracking and Assistive Technology
- High-pressure geophysics and materials
- Teleoperation and Haptic Systems
- Magnetic Properties of Alloys
- ZnO doping and properties
- Transition Metal Oxide Nanomaterials
- Magnetic properties of thin films
- Robotic Path Planning Algorithms
- Chalcogenide Semiconductor Thin Films
- Corporate Taxation and Avoidance
- Superconducting Materials and Applications
National Institute for Materials Science
2019-2025
Okayama University
2014-2023
Ritsumeikan University
2010-2020
Toyohashi University of Technology
2005-2019
Okayama University of Science
2015-2019
Institute for Molecular Science
2009-2010
Tohoku University
2003-2010
Purdue University West Lafayette
2004
Citizen (Japan)
2002
Shizuoka University
1991
The discovery of high-temperature superconductivity in iron pnictides raised the possibility an unconventional superconducting mechanism multiband materials. observation Fermi-surface (FS)-dependent nodeless gaps suggested that inter-FS interactions may play a crucial role pairing. In optimally hole-doped Ba(0.6)K(0.4)Fe(2)As(2), pairing strength is enhanced simultaneously (2Delta/T(c) approximately 7) on nearly nested FS pockets, i.e., inner hole-like (alpha) and 2 hybridized electron-like...
We study the possibility of superconductivity in a trilayer Ruddlesden-Popper nickelate ${\mathrm{La}}_{4}{\mathrm{Ni}}_{3}{\mathrm{O}}_{10}$ under pressure both theoretically and experimentally, making comparison with recently discovered high ${T}_{c}$ superconductor ${\mathrm{La}}_{3}{\mathrm{Ni}}_{2}{\mathrm{O}}_{7}$, bilayer nickelate. Through DFT calculations, we find that structural phase transition from monoclinic to tetragonal takes place around 10--15 GPa. Using crystal structure,...
Magnetic refrigeration exploits the magnetocaloric effect which is entropy change upon application and removal of magnetic fields in materials, providing an alternate path for other than conventional gas cycles. While intensive research has uncovered a vast number materials exhibits large effect, these properties compounds still remain unknown. To explore new functional this unknown space, machine learning used as guide selecting could exhibit effect. By approach, HoB$_{2}$ singled out,...
Abstract Exploration for superconducting metal diborides with a high critical temperature ( T c ) has attracted much attention since the discovery of MgB 2 . Recently reported in compressed MoB motivated us to investigate electrical transport property under pressure other diborides. We focused on relationship between and stretched c-lattice parameter / ), known as an important superconductivity , which shows main contribution p electron electronic structure. In this study, correlation is...
We performed high-resolution angle-resolved photoemission spectroscopy on electron-doped high-Tc superconductor Pr0.89LaCe0.11CuO4 to study the anisotropy of superconducting gap. The observed momentum dependence is basically consistent with dx2-y2-wave symmetry, but obviously deviates from monotonic dx2-y2 gap function. maximum not at zone boundary, hot spot where antiferromagnetic spin fluctuation strongly couples electrons Fermi surface. present experimental results unambiguously indicate...
The paper is concerned with the advanced control of liquid container transfer, special consideration given to suppression sloshing (liquid vibration) while maintaining a high speed transfer for container. In order construct system that satisfies reduction endpoint residual vibration and has robustness change in static level, suitable nominal model was adopted an appropriate reference trajectory determined by optimization method Fletcher Reeves (1964). Based on above command inputs using...
We performed high-resolution angle-resolved photoemission spectroscopy on ${\mathrm{N}\mathrm{d}}_{1.87}{\mathrm{C}\mathrm{e}}_{0.13}{\mathrm{C}\mathrm{u}\mathrm{O}}_{4}$, which is located at the boundary of antiferromagnetic (AF) and superconducting phase. observed that quasiparticle (QP) effective mass around $(\ensuremath{\pi},0)$ strongly enhanced due to opening AF gap. The QP gap are found be anisotropic, with largest value near intersecting point Fermi surface zone boundary. In...
We have performed high-resolution angle-resolved photoemission spectroscopy on heavily electron-doped non-superconducting (SC) BaFe1.7Co0.3As2. find that the two hole Fermi surface pockets at Brillouin zone center observed in hole-doped superconducting Ba0.6K0.4Fe2As2 are absent or very small this compound, while electron corner significantly expand due to doping by Co substitution. Comparison of between non-SC and SC samples indicates coexistence connected via antiferromagnetic wave vector...
We report high-resolution photoemission spectroscopy of newly-discovered iron-based layered superconductor La(O$_{0.93}$F$_{0.07}$)FeAs (Tc = 24 K). found that the superconducting gap shows a marked deviation from isotropic s-wave symmetry. The estimated size at 5 K is 3.6 meV in s- or axial p-wave case, while it 4.1 polar p- d-wave case. also pseudogap 15-20 above Tc, which gradually filled-in with increasing temperature and closes far Tc similarly to copper-oxide high-temperature superconductors.
The doping dependence of electronic states in an electron-doped high-temperature superconductor (HTSC) ${\mathrm{Nd}}_{2\ensuremath{-}x}{\mathrm{Ce}}_{x}\mathrm{Cu}{\mathrm{O}}_{4}$ was studied by high-resolution angle-resolved photoemission spectroscopy. We observed that the high-energy pseudogap around hot spot shows abrupt filling-in at magnet-superconductor phase boundary, resulting unusual reconstruction Fermi surface. magnitude $({\ensuremath{\Delta}}_{\mathrm{PG}})$ and temperature...
We performed high-resolution angle-resolved photoemission spectroscopy on La1.85Sr0.15CuO4 to study the nature of single-particle excitation gap. found that there is a well-defined superconducting coherence peak in off-nodal region while it strongly suppressed around antinode. The momentum dependence gap shows striking deviation from dx-y2--wave symmetry with anomalous enhancement antinode both and pseudogap state. observed close correlation between suggests substantial contribution behavior
High-resolution angle-resolved photoemission spectroscopy (ARPES) has been performed on a layered transition-metal dichalcogenide (TMDC) $1T\ensuremath{-}{\mathrm{VSe}}_{2}$ to study the $(4\ifmmode\times\else\texttimes\fi{}4)$ charge-density wave (CDW) mechanism. We observed partial Fermi-surface (FS) nesting electronlike FS centered at M (L) point. The spectral weight near ${E}_{F}$ is considerably suppressed below transition temperature ${(T}_{c}=110\mathrm{K})$ around nested portion,...
The autocorrelation of angle resolved photoemission data from the high temperature superconductor Bi2Sr2CaCu2O8+d shows distinct peaks in momentum space which disperse with binding energy superconducting state, but not pseudogap phase. Although it is tempting to attribute a non-dispersive behavior some ordering phenomenon, de-construction reveals that arise ordering, rather tips Fermi arcs, themselves do change energy.
The properties of ${\mathrm{Bi}}_{2}$${\mathrm{Sr}}_{2}$${\mathrm{CaCu}}_{2}$${\mathrm{O}}_{\mathit{y}}$ annealed at 200--650 \ifmmode^\circ\else\textdegree\fi{}C in vacuum (${10}^{\mathrm{\ensuremath{-}}4}$Pa) are studied by x-ray powder diffraction, ac magnetization, and Hall measurement. amount oxygen loss, \ensuremath{\Delta}y, was obtained an integration the partial pressure measured a quadrupole mass spectrometer. ${\mathit{T}}_{\mathit{c}}$ increases from 65 to 92 K, which is...
We report the fabrication of single-crystalline La-doped EuO thin films with a Curie temperature (TC) about 200 K, highest among rare-earth compounds without transition metals. From first-principle band calculation and x-ray diffraction measurement, observed increase in TC cannot be explained only by hybridization intensity due to lattice contraction up-spin electrons Eu 5d state caused electron doping. Hybridization between 4f donor states and/or Ruderman–Kittel–Kasuya–Yoshida interaction...
In plants in many industries, there exist a lot of transfer systems with vibration mechanisms. While without residual is usually demanded these plants, this requirement necessitates large numbers sensors and complicated models for control design. Therefore, This work presents trajectory design method to suppress the need directly measure vibration. The proposed consists two parts. First, frequency characteristics controller, comprised elements simple structures such as notch filter low-pass...
We have performed an ultrahigh-resolution angle-resolved photoemission spectroscopy study of slightly overdoped (Bi,Pb)2Sr2CuO6 to elucidate the origin pseudogap. By using a newly developed xenon-plasma light source, we determined comprehensive momentum and temperature dependencies superconducting gap found that antinodal pseudogap persists far above transition is smoothly connected nodal gap. The characteristic scales well with size irrespective location. present experimental results point pairing
We have investigated the electronic structures of recently discovered superconductor FeSe by soft-x-ray and hard-x-ray photoemission spectroscopy with high-bulk sensitivity. The large $\text{Fe}\text{ }3d$ spectral weight is located in vicinity Fermi level $({E}_{F})$, which demonstrated to be a coherent quasiparticle peak. Compared results band-structure calculation local-density approximation, band narrowing energy shift toward ${E}_{F}$ are found, suggesting an importance electron...
We have developed a new type of robot which accompanies the healthcare professionals making medical rounds in patient's bedrooms at hospitals. This novel mainly executes two tasks: carrying armamentarium round supplies and recording electronic health data on rounds. An omni-directional mobile mechanism human tracking control system to follow specified realize smooth transfer movement from nurses' station bedroom. Electronic is automatically recorded by using CCD camera voice recorder. When...
Mobile robot positioning in an indoor environment via fingerprinting technique is made by matching the unknown WiFi data to a spatial power map database. In past years, this has gained reasonable accuracies cost of high labor yielded for Thus, automatic database construction means interpolating missing desired. This paper described variation Inverse Distance Weight (IDW) interpolation which Modified Shepard's Method (MSM) our medical-oriented mobile - Terapio. By properly selecting reference...
Abstract The temperature dependence of the resistivity ( ρ ) Ag-doped Bi 2 Se 3 (Ag x 2−x shows insulating behavior above 35 K, but below suddenly decreases with decreasing temperature, in contrast to metallic for non-doped at 1.5–300 K. This significant change transport properties from clearly that Ag doping can effectively tune Fermi level downward. Hall effect measurement carrier is still electron and density changes reasonably explain properties. Furthermore, positive gating provides...
Diamond has two crystallographically inequivalent sites in the unit cell. In doped diamond, dopant occupation is expected to be equal. Nevertheless, preferential during growth under nonequilibrium conditions of fundamental importance, for example, enhance properties nitrogen-vacancy (N-V) centers; therefore, this a promising candidate qubit. However, lack suitable experimental techniques made it difficult study crystal- and chemical-site-resolved local structures dopants. Here, we confirm...
The superconducting transition temperature, ${T}_{\mathrm{c}}$, of FeSe can be significantly enhanced several-fold by applying pressure, electron doping, intercalating spacing layer, and reducing dimensionality. Various ordered electronic phases, such as nematicity spin density waves, have also been observed accompanying high-${T}_{\mathrm{c}}$ superconductivity. In this paper, we found a series discrete with maximum ${T}_{\mathrm{c}}$ up to 44 K, in ${\mathrm{H}}^{+}$-intercalated single...
We study the possibility of superconductivity in a trilayer Ruddlesden-Popper nickelate La$_4$Ni$_3$O$_{10}$ under pressure both theoretically and experimentally, making comparison with recently discovered high $T_c$ superconductor La$_3$Ni$_2$O$_7$, bilayer nickelate. Through DFT calculations, we find that structural phase transition from monoclinic to tetragonal takes place around 20 GPa. Using crystal structure, investigate superconductivity, where combination fluctuation exchange...