NMR relaxation and resistivity from rattling phonons in pyrochlore superconductors.
NMR relaxation and resistivity from rattling phonons in pyrochlore superconductors.
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DOI：
10.1103/physrevlett.99.187003
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发表时间：
2007-06
影响因子：
8.6
通讯作者：
T. Dahm;K. Ueda
中科院分区：
文献类型：
--
作者：
T. Dahm;K. Ueda
我们计算的NMR弛豫速率和电阻率耦合到一个本地的，强非谐声子模式的温度依赖性。我们认为，双声子拉曼过程是主导NMR弛豫。由于声子的强非谐性，发现了一种不寻常的温度依赖性，具有较低的温度峰值，并且在较高的温度下变得恒定。发现电阻率在低温下像T2一样变化，并且在高温下遵循平方根T行为。这两个结果是在定性协议与最近的观察β-烧绿石氧化物超导体。
We calculate the temperature dependence of the 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 T2 at low temperatures and following a square root T behavior at high temperatures. Both results are in qualitative agreement with recent observations on beta-pyrochlore oxide superconductors.