Nematic Resonance in the Raman Response of Iron-Based Superconductors.
Nematic Resonance in the Raman Response of Iron-Based Superconductors.
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DOI：
10.1103/physrevlett.116.017001
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发表时间：
2015-04
影响因子：
8.6
通讯作者：
Y. Gallais;I. Paul;L. Chauvière;J. Schmalian
中科院分区：
文献类型：
--
作者：
Y. Gallais;I. Paul;L. Chauvière;J. Schmalian
在全带隙超导体中，如果 Bogoliubov 激励不相关，则电子拉曼响应在超导带隙 Δ 的两倍处具有断对峰值。受铁基超导体的启发，我们研究了如果超导相具有向列结构量子临界点，该峰如何被修改。我们表明，通过调整（例如掺杂）接近这一点时，准粒子之间向列相关性的增长会将配对断裂峰转变为向列共振。模式能量低于 2Δ，并在量子临界点保持有限，其光谱权重急剧增强。后者与最近关于电子掺杂铁基超导体的实验一致，并提供了超导相向列相关性的直接证据。
In a fully gapped superconductor the electronic Raman response has a pair-breaking peak at twice the superconducting gap Δ, if the Bogoliubov excitations are uncorrelated. Motivated by the iron based superconductors, we study how this peak is modified if the superconducting phase hosts a nematic-structural quantum critical point. We show that, upon approaching this point by tuning, e.g., doping, the growth of nematic correlations between the quasiparticles transforms the pair-breaking peak into a nematic resonance. The mode energy is below 2Δ, and stays finite at the quantum critical point, where its spectral weight is sharply enhanced. The latter is consistent with recent experiments on electron-doped iron based superconductors and provides direct evidence of nematic correlations in their superconducting phases.