Leggett mode in a strong-coupling model of iron arsenide superconductors
Leggett mode in a strong-coupling model of iron arsenide superconductors
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DOI：
10.1103/physrevb.82.144506
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发表时间：
2010-10-11
影响因子：
3.7
通讯作者：
Bernevig, B. Andrei
中科院分区：
文献类型：
--
作者：
Burnell, F. J.;Hu, Jiangping;Bernevig, B. Andrei
使用一个双轨道模型的超导相的pnictides，我们计算的光谱的Leggett模式的集体激发的超导间隙的相位已知存在于多间隙超导体的超导序参量的不同可能的对称性。具体来说，我们确定的小区域的参数空间的莱格特模式低于两粒子连续，因此应该是可见的尖锐的共振峰。我们讨论了可能的效用的Leggett模式在区分不同的动量依赖的超导间隙。我们认为，观察到一个尖锐的Leggett模式将是一致的存在下，强的电子-电子相关的铁基超导体。我们还强调了莱格特模式轨道特征的重要性，这可以导致在A（1g）以外的通道中对该模式进行实验观察。
Using a two-orbital model of the superconducting phase of the pnictides, we compute the spectrum of the Leggett mode-a collective excitation of the phase of the superconducting gap known to exist in multigap superconductors-for different possible symmetries of the superconducting order parameter. Specifically, we identify the small regions of parameter space where the Leggett mode lies below the two-particle continuum, and hence should be visible as a sharp resonance peak. We discuss the possible utility of the Leggett mode in distinguishing different momentum dependencies of the superconducting gap. We argue that the observation of a sharp Leggett mode would be consistent with the presence of strong electron-electron correlations in iron-based superconductors. We also emphasize the importance of the orbital character of the Leggett mode, which can result in an experimental observation of the mode in channels other than A(1g).