Revising the 4 symmetry in CeCuGe; Soft X-ray absorption and hard X-ray photoemission spectroscopy

Aratani, Hidekazu*; Nakatani, Yasuhiro*; Fujiwara, Hidenori*; Kawada, Moeki*; Kanai, Yuina*; Yamagami, Kohei*; Fujioka, Shuhei*; Hamamoto, Satoru*; Kuga, Kentaro*; Kiss, Takayuki*; Yamasaki, Atsushi*; Higashiya, Atsushi*; Kadono, Toshiharu*; Imada, Shin*; Tanaka, Arata*; Tamasaku, Kenji*; Yabashi, Makina*; Ishikawa, Tetsuya*; Yasui, Akira*; Saito, Yuji  ; Narumi, Yasuo*; Kindo, Koichi*; Ebihara, Takao*; Sekiyama, Akira*

We present a detailed study on the ground state symmetry of the pressure-induced superconductor CeCuGe probed by soft X-ray absorption and hard X-ray photoemission spectroscopy. The revised Ce ground states are determined as with in-plane rotational symmetry. This gives an in-plane magnetic moment consistent with the antiferromagnetic moment as reported in neutron measurements. Since the in-plane symmetry is the same as that for the superconductor CeCuSi, we propose that the charge distribution along the -axis plays an essential role in driving the system into a superconducting phase.