Our group uses angle-resolved photoemission spectroscopy (ARPES) based on the light quantum hypothesis proposed by Einstein. When materials are irradiated with light (photons), electrons (photo-electrons) are emitted from the surface via the external photoelectric effect. We observe these photo-electrons with a state-of-the-art ultrahigh-resolution photoemission spectrometer constructed in our laboratory and elucidate the electronic states of various novel materials such as topological insulators and high-temperature superconductors.Read more