| CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES |
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Orbital Order and Orbital Excitations in Degenerate Itinerant Electron Systems |
| LU Feng1,2, SONG Yun3, CHEN Dong-Meng4, ZOU Liang-Jian1 |
| 1Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, PO Box 1129, Hefei 2300312Graduate School of the Chinese Academy of Sciences, Beijing 1001903 Department of Physics, Beijing Normal University, Beijing 1008754College of Physics Science and Technology, China University of Petroleum, Dongying 257061 |
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| Cite this article: |
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LU Feng, SONG Yun, CHEN Dong-Meng et al 2009 Chin. Phys. Lett. 26 097501 |
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Abstract We present a theory of orbital ordering in orbital-degenerate itinerant electron systems. The orbital instability in a two-orbital degenerate Hubbard model is investigated in the random phase approximation (RPA). After demonstrating the criteria for the formation of orbital ordering or the orbital density wave ordering, we find that the orbital and the spin-orbital collective excitation spectra in the ferro-orbital ordered phase exhibit finite gaps. The possible application of the present theory in orbital-ordered 4d compounds is also discussed.
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| Keywords:
75.10.Lp
75.30.Ds
75.40.Gb
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Received: 09 February 2009
Published: 28 August 2009
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