Flint, Rebecca, Nevidomskyy, Andriy H. and Coleman, Piers (2011) Composite pairing in a mixed-valent two-channel Anderson model. Physical Review B, 84 (6).
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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 CeCoIn5.
This is a Submitted version This version's date is: 23/8/2011 This item is not peer reviewed
https://repository.royalholloway.ac.uk/items/23571e43-17c3-ad46-3ea8-6a51f86a17f5/2/
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