Massless Leggett mode in three-band superconductors with time-reversal-symmetry breaking.
Massless Leggett mode in three-band superconductors with time-reversal-symmetry breaking.
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DOI：
10.1103/physrevlett.108.177005
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发表时间：
2011-07
影响因子：
8.6
通讯作者：
Shizeng Lin;X. Hu
中科院分区：
文献类型：
--
作者：
Shizeng Lin;X. Hu
多带超导体中超导相的异相振荡所伴随的Leggett模由于带间耦合而通常很重，这使得它的激发和检测变得困难。本文报道了具有时间反演对称性破缺的三带超导体中无质量Leggett模的存在。这种Leggett模式的质量在接近时间反演-超导破坏跃迁时很小，并且在跃迁点处消失，因此位于最小的超导能隙内，这使得它稳定且可检测，例如，通过拉曼光谱。这种无质量模式的热力学后果和可能实现的铁基超导体进行了讨论。
The Leggett mode associated with out-of-phase oscillations of the superconducting phase in multiband superconductors usually is heavy due to interband coupling, which makes its excitation and detection difficult. We report on the existence of a massless Leggett mode in three-band superconductors with time-reversal-symmetry breaking. The mass of this Leggett mode is small close to the time-reversal-symmetry-breaking transition and vanishes at the transition point, and thus locates within the smallest superconducting energy gap, which makes it stable and detectable, e.g., by means of the Raman spectroscopy. The thermodynamic consequences of this massless mode and possible realization in iron-based superconductors are also discussed.