Soft X-ray angle-resolved photoemission study of YbCuGe

Yasui, Akira; Fujimori, Shinichi   ; Kawasaki, Ikuto  ; Okane, Tetsuo  ; Takeda, Yukiharu   ; Saito, Yuji  ; Yamagami, Hiroshi; Sekiyama, Akira*; Settai, Rikio*; Matsuda, Tatsuma; Haga, Yoshinori   ; Onuki, Yoshichika*

Soft X-ray photoemission spectroscopies have been performed on YbCuGe, which is thought to be a Yb divalent system, to investigate its bulk electronic structure including Yb 4 electrons. Small but finite Yb multiplet peaks were found at 612 eV in the angle-integrated spectrum, suggesting that it is a valence fluctuation compound. An "anti-crossing" Yb 4 bands with conduction bands were observed in the angle-resolved spectrum. This is the evidence that the Yb 4 electrons form a band state through the hybridization with Ge 4 and Cu 3 electrons.