On the observation of the spin resonance in superconducting CeCoIn_5
Abstract
Recent observation of a resonance spin excitation at (1/2,1/2,1/2) in the superconducting state of CeCoIn_5 [C. Stock et al., Phys. Rev. Lett. {\bf 100} 087001 (2008)] was interpreted as an evidence for d_{x^2-y^2} gap symmetry, by analogy with the cuprates. This is true if the resonance is a spin exciton. We argue that such description is undermined by the three-dimensionality of CeCoIn_5. We show that in 3D systems the excitonic resonance only emerges at strong coupling, and is weak. We argue in favor of the alternative, magnon scenario, which does not require a d_{x^2-y^2} gap.
- Publication:
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arXiv e-prints
- Pub Date:
- April 2008
- DOI:
- 10.48550/arXiv.0804.2217
- arXiv:
- arXiv:0804.2217
- Bibcode:
- 2008arXiv0804.2217C
- Keywords:
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- Condensed Matter - Strongly Correlated Electrons
- E-Print:
- 5 pages, one figure