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Harada Group

Research Associate KIUCHI, Hisao

Research Subjects

  • Electronic structure analysis of aqueous solutions to study microheterogeneity and interaction at solid-liquid interfaces
  • Development of in situ soft X-ray spectroscopy for surface reaction of battery catalysts and electrodes, electrochemical reaction, photocatalytic reaction and functionality of metalloproteins
  • Study on the origin and observation of elementary excitations (crystal field excitation, spinon, magnon, charge density wave, orbiton) in strongly correlated materials
  • Basic study on ultrahigh energy resolution optics for soft X-ray emission and time-resolved spectroscopy

We explore the origin of the electronic structure of materials responsible for their electronic, magnetic and optical property using intense and energy tunable X-ray source: SPring-8, one of the most brilliant synchrotron facilities in the world. We have developed novel spectroscopies for material science in ‘soft’ X-ray region. We are leading the world’s soft X-ray emission spectroscopy, a kind of light scattering promising for electronic structure analyses of liquids and operando spectroscopy of a variety of catalysts. Our topics include a study on elementary excitations (crystal field excitation, spinon, magnon, charge density wave, orbiton etc.) in strongly correlated materials like Mott insulators and novel high-Tc superconductors, electronic structure analysis of aqueous solutions, interaction at solid-liquid interfaces, the surface reaction of battery catalysts and electrodes, electronic structure analysis of reaction center in metalloproteins, electrochemical and photocatalytic reactions. We also explore basic study on high performance soft X-ray absorption and emission spectroscopy for the next generation synchrotron light source.

Angle-resolved soft X-ray emission spectrometer with high energy resolution of 50 meV, originally developed by our laboratory at SPring-8, which is moved and will be operated at NanoTerasu from April 2024.
Soft X-ray emission spectroscopy has revealed that functional ionic liquid crystalline membranes with extremely uniform, nanometer-sized pores recognize the "hydrogen-bonded structure of water surrounding the ions" in order to selectively permeate specific ions.

Publications and Research Highlights