Phase fluctuations in strongly coupled d-wave superconductors.
Phase fluctuations in strongly coupled d-wave superconductors.
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DOI：
10.1103/physrevlett.94.217001
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发表时间：
2005-06
影响因子：
8.6
通讯作者：
M. Mayr;G. Alvarez;C. Şen;E. Dagotto
中科院分区：
文献类型：
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作者：
M. Mayr;G. Alvarez;C. Şen;E. Dagotto
我们提出了一个数值精确的解决方案，BCS哈密顿量在任何温度下，包括与经典相位相关的自由度，以及通过Monte Carlo积分的振幅波动。这使得调查的整个范围内的耦合：从弱吸引力，如在著名的BCS限制，主要是未开发的强耦合制度的显着相位波动。在后者中，两个特征温度T（*）和T（c），分别与短程和长程有序相关联，可以在平均场激发的哈密顿量中识别。T（*）同时对应于激发光谱中的间隙的打开。除了引入一个新的程序来研究强耦合d波超导体，我们的研究结果表明，经典的相位起伏是不足以解释高温超导体的赝能隙功能。
We present a numerically exact solution for the BCS Hamiltonian at any temperature, including the degrees of freedom associated with classical phase, as well as amplitude fluctuations via a Monte Carlo integration. This allows for an investigation over the whole range of couplings: from weak attraction, as in the well-known BCS limit, to the mainly unexplored strong-coupling regime of pronounced phase fluctuations. In the latter, two characteristic temperatures T(*) and T(c), associated with short- and long-range ordering, respectively, can be identified in a mean-field-motivated Hamiltonian. T(*) at the same time corresponds to the opening of a gap in the excitation spectrum. In addition to introducing a novel procedure to study strongly coupled d-wave superconductors, our results indicate that classical phase fluctuations are not sufficient to explain the pseudogap features of high-temperature superconductors.