A5047109593- Physics of Superconductivity and Magnetism
- Advanced Condensed Matter Physics
- Magnetic properties of thin films
- Magnetic and transport properties of perovskites and related materials
- Advanced Memory and Neural Computing
- Electronic and Structural Properties of Oxides
- Ionic liquids properties and applications
- Theoretical and Computational Physics
- Conducting polymers and applications
- Advanced Sensor and Energy Harvesting Materials
- Organic Electronics and Photovoltaics
- Innovative Energy Harvesting Technologies
- ZnO doping and properties
- Semiconductor materials and devices
- Iron-based superconductors research
- High-pressure geophysics and materials
- Superconductivity in MgB2 and Alloys
- Analytical Chemistry and Sensors
- Quantum and electron transport phenomena
- Energy Harvesting in Wireless Networks
- Gas Sensing Nanomaterials and Sensors
- Characterization and Applications of Magnetic Nanoparticles
- Electrochemical Analysis and Applications
- Inorganic Fluorides and Related Compounds
- Advanced Chemical Physics Studies
Tohoku University
2024-2025
Central Research Institute of Electric Power Industry
2015-2024
Nippon Medical School Hospital
2022-2024
Nippon Medical School
2022
Waseda University
2021
Nagasaki University
2020
Japan Science and Technology Agency
2019
Singulus (Germany)
2016-2017
RIKEN Center for Emergent Matter Science
2013-2016
Université Grenoble Alpes
2014-2016
Besides superconductivity, copper-oxide high temperature superconductors are susceptible to other types of ordering. We use scanning tunneling microscopy and resonant elastic x-ray scattering measurements establish the formation charge ordering in high-temperature superconductor Bi2Sr2CaCu2O8+x. Depending on hole concentration, this system occurs with same period as those found Y-based or La-based cuprates, displays analogous competition superconductivity. These results indicate similarity...
We report atomic-scale characterization of the pseudogap state in a high-Tc superconductor, Bi2Sr2CaCu2O(8+delta). The electronic states at low energies within exhibit spatial modulations having an energy-independent incommensurate periodicity. These patterns, which are oriented along copper-oxygen bond directions, appear to be consequence ordering phenomenon, observation correlates with density states. Our results provide stringent test for various scenarios cuprates, have been central...
Reversible electric-field control of the metal-insulator transition in rare earth nickelate compound NdNiO3 is demonstrated. Using electric double layer technique, giant modulations conductance as well large shifts temperature are obtained.
In the cuprate superconductors, Nernst and torque magnetization experiments have provided evidence that disappearance of Meissner effect at $T_c$ is caused by loss long-range phase coherence, rather than vanishing pair condensate. Here we report a series measurements on single crystals $\mathrm{La_{2-x}Sr_xCuO_4}$ (LSCO), $\mathrm{Bi_2Sr_{2-y}La_yCuO_6}$ (Bi 2201), $\mathrm{Bi_2Sr_2CaCu_2O_{8+\delta}}$ 2212) optimal $\mathrm{YBa_2Cu_3O_7}$. Some were taken to fields as high 45 T. Focusing...
The Hall effect and an increase of field-effect mobility with decreasing temperature is observerd in n-channel single-crystal organic transistors (OFETs). A quantitative analysis these findings, together results on different p-channel transistors, indicate the importance semiconductor molecular polarizability structure charge transport layers crystal for observation band-like OFETs. Detailed facts to specialist readers are published as "Supporting Information". Such documents peer-reviewed,...
We propose that resistivity curvature mapping (RCM) based on the in-plane data is a useful way to objectively draw electronic phase diagrams of high-Tc cuprates, where various crossovers are important. In particular, pseudogap crossover line can be conveniently determined by RCM. show experimental obtained RCM for Bi2Sr2-zLazCuO6+delta, La2-xSrxCuO4, and YBa2Cu3Oy, demonstrate universal nature crossover. Intriguingly, near optimum doping depicted appears occur rather abruptly, suggesting...
The diffusion of vortices down a thermal gradient produces Josephson signal which is detected as vortex Nernst effect. In recent report by Xu et al. [Nature 406, 486 (2000)], an enhanced identified with vortex-like excitations was observed in series ${\mathrm{La}}_{2\ensuremath{-}x}{\mathrm{Sr}}_{x}{\mathrm{CuO}}_{4}$ (LSCO) crystals at temperatures 50--100 K above ${T}_{c}.$ To pin the onset temperature ${T}_{\ensuremath{\nu}}$ vortexlike lightly doped regime $(0.03<~x<~0.07),$ we have...
We measure the normal-state in-plane resistivity of Bi(2)Sr(2-x)La(x)CuO(6+delta) single crystals at low temperatures by suppressing superconductivity with 60 T pulsed magnetic fields. With decreasing hole doping, we observe a crossover from metallic to an insulating behavior in low-temperature normal state. This is estimated occur near 1/8 well inside underdoped regime, and not optimum doping as reported for other cuprates. The regime marked logarithmic temperature dependence over two...
Although the Hall coefficient R_H is an informative transport property of metals and semiconductors, its meaning in cuprate superconductors has been ambiguous because unusual characteristics. Here we show that a systematic study La_{2-x}Sr_{x}CuO_{4} single crystals over wide doping range establishes qualitative understanding peculiar evolution, which turns out to reflect two-component nature electronic structure caused by development Fermi surface recently uncovered photoemission experiments.
Identifying the mechanism of superconductivity in high-temperature cuprate superconductors is one major outstanding problems physics. We report local measurements onset superconducting pairing high-transition temperature (Tc) superconductor Bi2Sr2CaCu2O8+delta using a lattice-tracking spectroscopy technique with scanning tunneling microscope. can determine dependence energy gaps, electronic excitations absence pairing, and effect coupling electrons to bosonic excitations. Our reveal that...
We report high-mobility rubrene single-crystal field-effect transistors with ionic-liquid (IL) electrolytes used for gate dielectric layers. As the result of fast ionic diffusion to form electric double layers, their capacitances remain more than 1μF∕cm2 even at 0.1MHz. With high carrier mobility 1.2cm2∕Vs in crystal, pronounced current amplification is achieved voltage only 0.2V, which two orders magnitude smaller that necessary organic thin-film insulators. The results demonstrate...
We have determined the upper critical field Hc2 as a function of hole concentration in bismuth-based cuprates by measuring voltage induced vortex flow driving temperature gradient (the Nernst effect), magnetic fields up to 45 tesla. found that decreased steeply doping increased, both single and bilayer cuprates. This relationship implies Cooper pairing potential displays trend opposite superfluid density versus doping. The coherence length pairs xi(0) closely tracks gap measured...
We report on a comparative study of rubrene single-crystal field-effect transistors with various ionic-liquid electrolytes used for gate insulators. A systematic correlation is found that mobility the increases decreasing electrostatic capacitance electric double layers, as result highly reproducible comparisons among tens samples variation anions in purified ionic liquids. By optimizing gating liquid, highest electrolyte-gated organic elevated up to 9.5 cm2/V s, which only fraction value...
The electric field effect on magnetization properties and Curie temperature of Co ultra-thin films has been investigated. An is applied to a film by using an double layer (EDL) formed in polymer containing ionic liquid. change the ∼100 K applying gate voltage ±2 V, suggesting that observed large modifications are attributed significant temperature, which induced amount carrier density control due formation EDL.
The Dzyaloshinskii-Moriya Interaction (DMI) is a key ingredient for the observation of skyrmions and N\'eel domain walls in films with perpendicular magnetic anisotropy. dynamic control DMI is, therefore, great interest developing chirality-dependent spintronics. This study demonstrates nonvolatile modification anisotropy through electric-field-induced ionic migration Pt/Co/HfO${}_{2}$/liquid-gate structures. As liquid gate can be removed after applying electric field, this not only step...
Materials tuned to a quantum critical point display universal scaling properties as function of temperature $T$ and frequency $\omega$. A long-standing puzzle regarding cuprate superconductors has been the observed power-law dependence optical conductivity with an exponent smaller than one, in contrast $T$-linear resistivity $\omega$-linear scattering rate. Here, we present analyze La$_{2-x}$Sr$_x$CuO$_4$ $x=0.24$. We demonstrate $\hbar\omega/k_{\mathrm{B}} T$ data over wide range...
Using scanning tunneling spectroscopy, we investigated the temperature dependence of quasiparticle density states overdoped Bi(2)Sr(2)CuO(6+delta) between 275 mK and 82 K. Below T(c) = 10 K, spectra show a gap with well-defined coherence peaks at +/-Delta(p) approximately 12 meV, which disappear T(c). Above T(c), display clear pseudogap same magnitude, gradually filling up vanishing T(*) 68 The comparison Bi(2)Sr(2)CaCu(2)O(8+delta) demonstrates that superconducting scale each other,...
We investigate the hole dynamics in two prototypical high temperature superconducting systems: ${\mathrm{La}}_{2\ensuremath{-}x}{\mathrm{Sr}}_{x}\mathrm{Cu}{\mathrm{O}}_{4}$ and $\mathrm{Y}{\mathrm{Ba}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{y}$, using a combination of dc transport infrared spectroscopy. By exploring effective spectral weight obtained with optics conjunction Hall results, we find that transition to Mott insulating state these systems is ``vanishing carrier number'' type since...