Hybridization and suppression of the superconductivity in CeFeAsO_1-y. Pressure and temperature dependences of the electronic structure

Journal Article · Thu Sep 23 04:00:00 EDT 2010 · Phys. Rev. B

DOI:https://doi.org/10.1103/PhysRevB.82.125123· OSTI ID:1065307

Yamaoka, Hitoshi ^[1]; Jarrige, Ignace ^[2]; Ikeda-Ohno, Atsushi ^[2]; Tsutsui, Satoshi ^[3]; Lin, Jung-Fu ^[4]; Takeshita, Nao ^[5]; Miyazawa, Kiichi ^[6]; Iyo, Akira ^[6]; Kito, Hijiri ^[5]; Eisaki, Hiroshi ^[5]; Hiraoka, Nozomu ^[7]; Ishii, Hirofumi ^[7]; Tsuei, Ku-Ding ^[7]

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1. Inst. of Physical and Chemical Research (RIKEN), Wako (Japan)
2. Japan Atomic Energy Agency (JAEA), Hyogo (Japan)
3. Japan Synchrotron Radiation Research Inst., Hyogo (Japan)
4. Univ. of Texas, Austin, TX (United States)
5. National Inst. of Advanced Industrial Science adn Technology (AIST), Ibaraki (Japan); Transformative Research-Project on Iron Pnictides (TRIP), Tokyo (Japan)
6. National Inst. of Advanced Industrial Science adn Technology (AIST), Ibaraki (Japan); Transformative Research-Project on Iron Pnictides (TRIP), Tokyo (Japan); Tokyo Univ. of Science, Chiba (Japan)
7. National Synchrotron Radiation Research Center, Hsinchu (Taiwan)

Pressure and temperature dependence of the electronic structure of superconducting (SC) CeFeAsO_1-y and non-SC CeFeAsO_1-y have been investigated using two complementary hard x-ray spectroscopic probes at the Ce L₃ edge, partial fluorescence yield x-ray absorption spectroscopy and resonant x-ray emission spectroscopy. With increasing pressure, the ratio between the intensity of the peak related to the f⁰ (Ce⁴⁺ ) state and that of the f¹ (Ce³⁺ ) state, I(f⁰)/I(f¹ ), is found to increase continuously for both compounds, indicating a continuous increase in the Ce valence. The valence of non-SC CeFeAsO_1-y is found to be slightly higher than that of SC CeFeAsO_1-y in the entire pressure and temperature ranges of this study. The valence of CeFeAsO_1-y around 6 GPa, where the superconductivity breaks down, is estimated to be ~3.0 , but no change in the valence is observed upon cooling. The dependence of the interatomic distances on the concentration of oxygen vacancies is studied via extended absorption fine structure spectroscopy.

• Research Organization: Energy Frontier Research Centers (EFRC); Energy Frontier Research in Extreme Environments (EFree)
• Sponsoring Organization: USDOE SC Office of Basic Energy Sciences (SC-22)
• DOE Contract Number: SC0001057
• OSTI ID: 1065307
• Journal Information: Phys. Rev. B, Journal Name: Phys. Rev. B Vol. 82
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English

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75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
catalysis (heterogeneous)
charge transport
energy storage (including batteries and capacitors)
hydrogen and fuel cells
materials and chemistry by design
mesostructured materials
phonons
solar (photovoltaic)
superconductivity
synthesis (novel materials)
thermoelectric