Bulk-sensitive photoemission study of A Cu3 Ru4 O12 (A=Ca, Na, and La) with heavy-fermion behavior

Takaaki Sudayama*, Yuki Wakisaka, Kou Takubo, Takashi Mizokawa, Wataru Kobayashi, Ichiro Terasaki, Soutarou Tanaka, Yoshiteru Maeno, Masashi Arita, Hirofumi Namatame, Masaki Taniguchi

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)


We have studied the d -electron heavy-fermion states in A Cu3 Ru4 O12 (A=Ca, Na, and La) using x-ray photoemission spectroscopy and high-resolution photoemission spectroscopy at bulk-sensitive photon energy (7 eV). The bulk-sensitive photoemission measurements for A=Ca, Na, and La show that a resonancelike structure within a pseudogap commonly evolves in the low-temperature range where the Kadowaki-Woods relation holds. The origin of the resonancelike peak and the heavy-fermion behavior is basically attributed to the hybridization between the Cu3d and Ru4d orbitals. The A -site substitution controls the filling of the Cu3d and Ru 4d hybridized bands. Interestingly, while the resonancelike peak position roughly follows the rigid-band shift for A=Na and La, the resonancelike peak deviating from the rigid-band behavior is located just at the Fermi level as expected in a Kondo system. The difference in the resonancelike peak near the Fermi level is correlated with that in the Cu2p core-level spectra.

Original languageEnglish
Article number075113
JournalPhysical Review B - Condensed Matter and Materials Physics
Issue number7
Publication statusPublished - 2009 Aug 14
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics


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