Cooperative Effect of Coulomb Interaction and Electron-Phonon Coupling on the Heavy Fermion State in the Two-Orbital Periodic Anderson Model
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Abstract
We investigate the two-orbital periodic Anderson model, where the local orbital fluctuations of f-electrons couple with a two-fold degenerate Jahn-Teller phonon, by using the dynamical mean-field theory. It is found that the heavy fermion state caused by the Coulomb interaction between f-electrons U is largely enhanced due to the electron-phonon coupling g, in contrast to the case with the single-orbital periodic Anderson model where the effects of U and g compete to each other. In the heavy fermion state for large U and g, both the orbital and lattice fluctuations are enhanced, while the charge (valence) and spin fluctuations are suppressed. In the strong coupling regime, a sharp soft phonon mode with a large spectral weight is observed for small U, while a broad soft phonon mode with a small spectral weight is observed for large U. The cooperative effect of U and g for half-filling with two f-electrons per atom nf = 2 is more pronounced than that for quarter-filling with nf = 1.
Journal
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- Journal of the Physical Society of Japan
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Journal of the Physical Society of Japan 79 (5), 054707-1-054707-7, 2010-05
日本物理学会
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Details 詳細情報について
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- CRID
- 1050845764171121536
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- NII Article ID
- 40017104681
- 120006746796
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- NII Book ID
- AA00704814
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- ISSN
- 00319015
- 13474073
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- HANDLE
- 10191/26839
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- NDL BIB ID
- 10675228
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- Text Lang
- en
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- Article Type
- journal article
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- Data Source
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- IRDB
- NDL
- Crossref
- CiNii Articles
- KAKEN