Electronic structure of Kondo lattice compounds YbNi3X9 (X = Al, Ga) studied by hard x-ray spectroscopy

Utsumi Yuki

Sato Hitoshi

Ohara Shigeo

Yamashita Tetsuro

Mimura Kojiro

Motonami Satoru

Shimada Kenya

Ueda Shigenori

Kobayashi Keisuke

Yamaoka Hitoshi

Tsujii Naohito

Hiraoka Nozomu

Namatame Hirofumi

Taniguchi Masaki

Physical Review B

We have performed hard x-ray photoemission spectroscopy (HAXPES) for Yb-based Kondo lattice compounds; an antiferromagnetic heavy-fermion system YbNi3Al9 and a valence fluctuation system YbNi3Ga9. The Yb 3d5/2 spectra of YbNi3Ga9 showed both Yb2+ and Yb3+-derived structures indicating strong valence fluctuation, and the intensity of Yb2+ (Yb3+) structures gradually increased (decreased) on cooling. The Yb 3d5/2 spectra of YbNi3Al9 mostly consisted of Yb3+-derived structures and showed little temperature dependence. The Yb valences of YbNi3Ga9 and YbNi3Al9 at 22 K were evaluated to be 2.43 and 2.97, respectively. Based on the results of the Ni 2p and valence-band HAXPES spectra together with soft x-ray valence-band spectra, we described that the difference of physical properties of YbNi3X9 (X= Al, Ga) is derived from the differences of the 4f-hole level relative to the Fermi level (EF) and Ni 3d density of states at EF. The HAXPES results on the Yb valences were consistent with those obtained by x-ray absorption spectroscopy using the partial fluorescence yield mode and resonant x-ray emission spectroscopy at the Yb L3 edge.

Physics [ 420 ]

eng

American Physical Society

(c) 2012 American Physical Society

[ISSN] 1098-0121

[DOI] 10.1103/PhysRevB.86.115114

[NCID] AA11187113

[DOI] http://dx.doi.org/10.1103/PhysRevB.86.115114