VIII-J-9 Mixed Valence of Yb₃S₄

Shin-ichi KIMURA,* Yong Seung KWON* and Takashi SUZUKI** (*Sung Kyun Kwan Univ. Korea, **Tohoku Univ.)

[Physica B 301, 230 (1997)]

Reflectivity and photoemission spectra of a mixed valence semiconductor, Yb₃S₄, were measured for the investigation of the electronic structure and the mean valence. The mean valence was determined to be 2.67 by the 4f and 5p photoemission spectra. The energy gap was recognized to be 0.4 eV by the optical conductivity spectrum but the absorption coefficient is small. The energy gap is considered to consists of the occupied S-3p and the unoccupied Yb₃₊-4f states.

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