Electronic Structure of Superconducting and Non-superconducting Pr2Ba4Cu7O15-[delta] Revealed by Photoemission Spectroscopy

• Published in: Journal of the Physical Society of Japan 2008-07, Vol.77 (7)
• Main Authors: Wakisaka, Yuki, Takubo, Kou, Sudayama, Takaaki, Son, Jin-Young, Mizokawa, Takashi, Arita, Masashi, Namatame, Hirofumi, Taniguchi, Masaki, Sekiya, Syun, Fukuda, Kazunori, Ishikawa, Fumihiro, Yamada, Yuh
• Format: Article
• Language: English
• ISSN: 0031-9015; 1347-4073

In order to understand the nature of chain-driven superconductivity in Pr2Ba4Cu7O15-δ (Pr247), we have studied the electronic structure of as-sintered non-superconducting Pr247 and annealed superconducting Pr247 samples using photoemission spectroscopy. The O 1s, Ba 3d, Pr 4d, and Cu 2p core-level energy shifts by annealing indicate that electrons doped by the annealing mainly fill the localized Fehrenbacher-Rice (FR) state. The photoemission spectra ρ(ω) near the Fermi level (EF) are derived from the metallic Cu-O double chain and can be fitted to the power-law function plus step function Aωα+Bθ(ω). ρ(ω) near EF is indistinguishable between the as-sintered and annealed Pr247 and the exponent α is ∼1.5. These results indicate that the Cu-O double chain provides the spectral weight near EF and that the annealing affects the localized FR state instead of the near-EF state.