Composite pairing in a mixed-valent two-channel Anderson model
Author(s)
Nevidomskyy, Andriy H.; Coleman, Piers; Flint, Rebecca
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Using a two-channel Anderson model, we develop a theory of composite pairing in the 115 family of heavy fermion superconductors that incorporates the effects of f-electron valence fluctuations. Our calculations introduce “symplectic Hubbard operators”: an extension of the slave boson Hubbard operators that preserves both spin rotation and time-reversal symmetry in a large N expansion, permitting a unified treatment of anisotropic singlet pairing and valence fluctuations. We find that the development of composite pairing in the presence of valence fluctuations manifests itself as a phase-coherent mixing of the empty and doubly occupied configurations of the mixed valent ion. This effect redistributes the f-electron charge within the unit cell. Our theory predicts a sharp superconducting shift in the nuclear quadrupole resonance frequency associated with this redistribution. We calculate the magnitude and sign of the predicted shift expected in CeCoIn[subscript 5].
Date issued
2011-08Department
Massachusetts Institute of Technology. Department of PhysicsJournal
Physical Review B
Publisher
American Physical Society (APS)
Citation
Flint, Rebecca, Andriy Nevidomskyy, and Piers Coleman. “Composite Pairing in a Mixed-valent Two-channel Anderson Model.” Physical Review B 84.6 (2011): n. pag. Web. 17 Feb. 2012. © 2011 American Physical Society
Version: Final published version
ISSN
1098-0121
1550-235X