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arXiv · 0903.2291

Universal relation between magnetic resonance and superconducting gap in unconventional superconductors

G. Yu·Y. Li·E. M. Motoyama·M. Greven
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Abstract

Unconventional superconductors such as the high-transition temperature cuprates, heavy-fermion systems and iron arsenide-based compounds exhibit antiferromagnetic fluctuations that are dominated by a resonance, a collective spin-one excitation mode in the superconducting state. Here we demonstrate the existence of a universal linear relation, $Er \propto 2Δ$, between the magnetic resonance energy (Er) and the superconducting pairing gap ($Δ$), spanning two orders of magnitude in energy. This relation is valid for materials that range from being close to the Mott-insulating limit to being on the border of itinerant magnetism. Since the common excitonic picture of the resonance has not led to such universality, our observation suggests a much deeper connection between antiferromagnetic fluctuations and unconventional superconductivity.

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G. Yu, Y. Li, E. M. Motoyama, M. Greven. 2009-03-12. Universal relation between magnetic resonance and superconducting gap in unconventional superconductors. https://doi.org/10.1038/nphys1426

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