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

Okane, Tetsuo  ; Fujimori, Shinichi   ; Mamiya, Kazutoshi; Okamoto, Jun; Muramatsu, Yasuji; Fujimori, Atsushi; Suzuki, Hiroyuki*; Matsumoto, Takehiko*; Furubayashi, Takao*; Isobe, Masaaki*; Nagata, Shoichi*

The electronic structure of spinel-type chalcogenide CuIrS, which exhibits a metal-insulator transition (MIT) as a function of temperature, has been studied by photoemission spectroscopy (PES). Below the transition temperature , the valence-band PES spectra indicate a gap formation, while the overall valence-band structure is shifted to the higher binding-energy side. The line shape of the Ir 4 core-level PES spectra shows a dramatic change across , which may be associated with the variation of the Ir 5 electron states.