The Shimada-Ideta Group of Hiroshima Synchrotron Radiation Center (HiSOR) at Hiroshima University is mainly performed in research on the electronic structure and functionality of materials called strongly correlated electron systems (superconductors, metal insulators, etc.) and topological insulators by angle-resolved photoemission spectroscopy using highly brilliant and synchrotron light (synchrotron radiation). In strongly correlated electron systems, the electron density is so high that electrons strongly interact with each other and the band theory, which is the basic theory of solid state physics, does not explain the physical propertis anymore. Such strongly correlated electron systems exhibit a wide variety of interesting physical properties such as high-temperature superconductivity, giant magnetoresistance, and non-Fermi liquid. By controlling the charge, spin, and orbital of electrons, these materials have the potential to become electronic devices for spintronics and strongly correlated electronics that surpass conventional electronics, and are expected to play a key role in the next generation of electronics. The electronic states near the Fermi level of these materials are responsible for their diverse functionalities, and the observation of these electronic states is very important and indispensable for the discovery of new materials and properties.

　Our group perform researches to directly observe the electronic states by using synchrotron radiation from HiSOR to perform spectroscopic experiments on the strongly correlated materials and so on. Synchrotron radiation is a continuous wavelengths from the terahertz/far infrared to the X-ray regions, and its high brightness and excellent controlled polarization enable us to perform completely new spectroscopic experiments that are different from those in the laboratory. We furthermore perform angle-resolved photoemission spectroscopy (ARPES) experiments usinglasers as a light source. We also develop instruments extensively and new spectroscopic techniques using synchrotron and laser light source to observe the electronic structure that gives rise to novel fanctionalities and interesting physical properties in various materials.

Research Highlight

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