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arXiv · 0706.4345

NMR relaxation and resistivity from rattling phonons in pyrochlore superconductors

Thomas Dahm·Kazuo Ueda
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Abstract

We calculate the temperature dependence of NMR relaxation rate and electrical resistivity for coupling to a local, strongly anharmonic phonon mode. We argue that the two-phonon Raman process is dominating NMR relaxation. Due to the strong anharmonicity of the phonon an unusual temperature dependence is found having a low temperature peak and becoming constant towards higher temperatures. The electrical resistivity is found to vary like T^2 at low temperatures and following a sqrt{T} behavior at high temperatures. Both results are in qualitative agreement with recent observations on beta-pyrochlore oxide superconductors.

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Thomas Dahm, Kazuo Ueda. 2007-09-17. NMR relaxation and resistivity from rattling phonons in pyrochlore superconductors. https://doi.org/10.1103/physrevlett.99.187003

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