caa a22 4500 44538039X CHVBK 20180317143015.0 cr unu---uuuuu 170323e20110401xx s 000 0 eng 10.1007/s10948-010-1095-z doi (NATIONALLICENCE)springer-10.1007/s10948-010-1095-z Electronic Structure ofBaFe2− x Co x As2 Revealed byAngle-Resolved Photoemission Spectroscopy [Elektronische Daten] [T. Mizokawa, T. Sudayama, Y. Wakisaka, R. Morinaga, T. Sato, M. Arita, H. Namatame, M. Taniguchi, N. Saini] We report an angle-resolved photoemission spectroscopy study of BaFe2−x CoxAs2. For x=0, above the structural and magnetic transition temperature (T s), the spectral weight near the Fermi level is considerably suppressed around the Γ point where the Fe 3d yz/zx orbital degeneracy is expected. This observation suggests that the Jahn-Teller type instability is playing an important role in the tetragonal phase aboveT s. Below T s, the spectral weight of 0-100 meV is reconstructed to form flat bands at 70-100meV and Fermi surfaces, consistent with the orbital-dependent excitonic coupling. In the optimally doped and overdoped regimes, the hole pocket around the Γ point and the electron pocket around the M point are apparently nested, indicating that the doping dependence of the superconducting transition temperature cannot be explained by the nesting scenario and that the unusual electron-lattice fluctuation due to the orbital degeneracy is important. Springer Science+Business Media, LLC, 2010 ARPES nationallicence FeAs layer nationallicence Orbital degeneracy nationallicence Excitonic insulator nationallicence Mizokawa T. Department of Complexity Science and Engineering & Department of Physics, University of Tokyo, 5-1-5 Kashiwanoha, 277-8561, Chiba, Japan aut Sudayama T. Department of Complexity Science and Engineering & Department of Physics, University of Tokyo, 5-1-5 Kashiwanoha, 277-8561, Chiba, Japan aut Wakisaka Y. Department of Complexity Science and Engineering & Department of Physics, University of Tokyo, 5-1-5 Kashiwanoha, 277-8561, Chiba, Japan aut Morinaga R. Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, 277-8581, Chiba, Japan aut Sato T. Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, 277-8581, Chiba, Japan aut Arita M. Hiroshima Synchrotron Radiation Center, Hiroshima University, 739-0046, Higashihiroshima, Hiroshima, Japan aut Namatame H. Hiroshima Synchrotron Radiation Center, Hiroshima University, 739-0046, Higashihiroshima, Hiroshima, Japan aut Taniguchi M. Hiroshima Synchrotron Radiation Center, Hiroshima University, 739-0046, Higashihiroshima, Hiroshima, Japan aut Saini N. Department of Complexity Science and Engineering & Department of Physics, University of Tokyo, 5-1-5 Kashiwanoha, 277-8561, Chiba, Japan aut Journal of Superconductivity and Novel Magnetism Springer US; http://www.springer-ny.com 24/3(2011-04-01), 1133-1136 1557-1939 24:3<1133 2011 24 10948 https://doi.org/10.1007/s10948-010-1095-z text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10948-010-1095-z text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Mizokawa T. Department of Complexity Science and Engineering & Department of Physics, University of Tokyo, 5-1-5 Kashiwanoha, 277-8561, Chiba, Japan aut NATIONALLICENCE 700 1- Sudayama T. Department of Complexity Science and Engineering & Department of Physics, University of Tokyo, 5-1-5 Kashiwanoha, 277-8561, Chiba, Japan aut NATIONALLICENCE 700 1- Wakisaka Y. Department of Complexity Science and Engineering & Department of Physics, University of Tokyo, 5-1-5 Kashiwanoha, 277-8561, Chiba, Japan aut NATIONALLICENCE 700 1- Morinaga R. Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, 277-8581, Chiba, Japan aut NATIONALLICENCE 700 1- Sato T. Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, 277-8581, Chiba, Japan aut NATIONALLICENCE 700 1- Arita M. Hiroshima Synchrotron Radiation Center, Hiroshima University, 739-0046, Higashihiroshima, Hiroshima, Japan aut NATIONALLICENCE 700 1- Namatame H. Hiroshima Synchrotron Radiation Center, Hiroshima University, 739-0046, Higashihiroshima, Hiroshima, Japan aut NATIONALLICENCE 700 1- Taniguchi M. Hiroshima Synchrotron Radiation Center, Hiroshima University, 739-0046, Higashihiroshima, Hiroshima, Japan aut NATIONALLICENCE 700 1- Saini N. Department of Complexity Science and Engineering & Department of Physics, University of Tokyo, 5-1-5 Kashiwanoha, 277-8561, Chiba, Japan aut NATIONALLICENCE 773 0- Journal of Superconductivity and Novel Magnetism Springer US; http://www.springer-ny.com 24/3(2011-04-01), 1133-1136 1557-1939 24:3<1133 2011 24 10948 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer