Abstract
We use the two fluid model to determine the conditions under which the nuclear spin-lattice lattice relaxation rate of candidate heavy quantum critical superconductors can exhibit scaling behavior and find that it can occur if and only if their “hidden” quantum critical spin fluctuations give rise to a temperature-independent intrinsic heavy electron spin-lattice relaxation rate. The resulting scaling of with the strength of the heavy electron component and the coherence temperature provides a simple test for their presence at pressures at which the superconducting transition temperature is maximum and is proportional to . These findings support the previously noted partial scaling of the spin-lattice relaxation rate with in a number of important heavy electron materials and provide additional evidence that in these materials their optimal superconductivity originates in the quantum critical spin fluctuations associated with a nearby phase transition from partially localized to fully itinerant quasiparticles.
- Received 2 October 2014
- Revised 2 November 2015
DOI:https://doi.org/10.1103/PhysRevB.92.195131
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