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I. Matsuda Group

Research Associate HORIO, Masafumi

Research Subjects

  • Dirac Fermions in monatomic layers
  • Study of non-linear X-ray spectroscopy by X-ray free electron laser
  • operando X-ray experiments to study molecule and carrier dynamics at surfaces
  • Developments of frontier technologies for undulator beamlines of the next generation synchrotron radiation

We have developed advanced techniques for absorption spectroscopy, photoelectron spectroscopy, and nonlinear spectroscopy using vacuum ultraviolet rays to soft X-rays, generated from high-intensity synchrotron radiation, X-ray free electron lasers, and high-order harmonic generation lasers. With our completed spectroscopy systems, we have conducted operando experiments to “in situ” observe any changes of the material states under the operation conditions of functionalities. Using the characteristics of each light source, the dynamic changes in each time scale from femtoseconds to milliseconds are tracked in real time to clarify the details and a series of the temporal information is chronically connected to capture the whole picture of the dynamic phenomenon. In our laboratory, we are mainly studying physical properties and functionalities of monoatomic layers with exotic Dirac Fermions and at surfaces/interfaces of strongly correlated materials. We manage and operate high-brilliant soft X-ray beamline BL07LSU at SPring-8. We are also devoting ourselves in constructions of beamlines for the next-generation synchrotron radiation facility.

A collection of monatomic layers with various types of Dirac Fermions that are synthesized and examined in our group.
The soft X-ray second harmonic generation (SHG) and the Fe 3p resonant effect in the GaFeO3 crystal using free electron laser. (a) The measurement set-up and (b) the absorption spectrum. Intensity, I, of (c) the fundamental (ħω = 27.5 eV), (d,e) SHG (2ħω = 55 and 53eV) with respect to the incident intensity, I0.

Publications and Research Highlights