High-resolution soft X-ray photoemission spectroscopy of spinel-type compound CuIr2S4

Abstract The electronic structure of spinel-type chalcogenide CuIr 2 S 4 , which exhibits a metal–insulator transition, has been studied by photoemission spectroscopy (PES). The valence-band PES spectra indicate a gap formation below the transition temperature T MI . The line shape of the Ir 4f core-level PES spectra shows a dramatic change across T MI , which may be associated with the variation of the Ir 5d electron states.