Recent Raman scattering data in B_{1g} and B_{2g} geometries in the superconducting state of underdoped cuprates were interpreted as evidence for two distinct energy gaps. We argue that these data can be equally well explained within a one gap scenario if final state interactions are taken into account. In particular, we show that they can account for the differing doping dependences of the Raman peaks in these two geometries.
The Raman scattering with local optical excitation from the Majorana edge modes of Kitaev spin liquids and topological superconductors is studied theoretically. Although the effective one-dimensional model is common between these two cases, the coupling to the electromagnetic field is different. It is found that the Raman spectrum at low energy scales with $ω^3$ in Kitaev spin liquids while it shows the gap in topological superconductors. This is in sharp contrast to the infrared absorption, where the spectrum shows the gap in Kitaev spin liquids, while it behaves as $\sim ω^2$ in topological …
The pressure dependence of many-body interactions in the organic superconductor $κ$-(BEDT-TTF)$_{2}$Cu(SCN)$_{2}$: A comparison of high pressure infrared reflectivity and Raman scattering experiments
Linear Response Theory for Shear Modulus $C_{66}$ and Raman Quadrupole Susceptibility: Significant Evidence for Orbital Nematic Fluctuations in Fe-Based Superconductors
Raman scattering as a probe of charge nematic fluctuations in iron based superconductors
本文报道了BaFe $_2$ As $_2$和Sr（Fe $_{1-x}$ Co $_x$）$_2$ As $_2$（x=0.04）单晶四元相中电荷涨落的拉曼散射测量。在这两个系统中，所观察到的居里-外斯波动被发现表现出发散的居里-外斯行为与非常相似的特征温度标度，表明在122铁基超导体的普遍趋势，对电荷的有序。
Charge Nematicity and Electronic Raman Scattering in Iron-based Superconductors
本文综述了铁基超导体中电荷涨落的电子喇曼散射测量的最新进展。一个简单的理论框架的$d$波波Pomeranchuk过渡，提出了为了捕捉显着的特点的频谱。我们讨论了122个铁基体系，特别是Co掺杂BaFe $_2$ As $_2$正常态的拉曼光谱数据，我们发现，低能量准弹性峰，提取的磁化率和散射率是一致的电子驱动的结构相变。在全能隙超导态下，准弹性峰转变为有限频率的共振，这在电子掺杂系统中表现得尤为明显。分析的一个重要特征是电子拉曼信号不受声学声子的影响。这使得拉曼光谱成为电子向列性的独特探针。
Relationship among superconductivity, pseudogap, and high-energy magnetic fluctuations in a model high-Tc superconductor from electronic Raman scattering
Screening in (d+s)-wave superconductors: Application to Raman scattering
采用各向异性跳跃矩阵参数的紧束缚带结构和$d$ -和s-波对称混合的超导能隙隙，研究了非孪晶YBa $_2$ Cu $_3$ O $_{7-δ}$超导体的极化相关电子喇曼响应.使用一般的参数，我们发现屏蔽条款的$B^{\}_{1g}$散射通道所需的规范不变性。其结果是，我们得到了一个小的，但可测量的软化的对破峰，其位置已被归因于长期以来的两倍的超导能隙最大值。此外，我们预测超导引起的声子线形状的变化，可以提供一种方法来检测各向同性s波混合物的超导能隙。
The FeSe-based superconductors exhibit a wide range of critical temperature Tc under a variety of material and physical conditions, but extensive studies to date have yet to produce a consensus view on the underlying mechanism. Here we report on a systematic Raman scattering work on intercalated FeSe superconductors Lix(NH3)yFe2Se2 and (Li,Fe)OHFeSe compared to pristine FeSe. All three crystals show an anomalous power-law temperature dependence of phonon linewidths, deviating from the standard anharmonic behavior. This intriguing phenomenon is attributed to electron-phonon coupling effects enh…
The pseudogap regime of the cuprate high-temperature superconductors is characterized by a variety of competing orders, the nature of which are still widely debated. Recent experiments have provided evidence for electron nematic order, in which the electron fluid breaks rotational symmetry while preserving translational invariance. Raman spectroscopy, with its ability to symmetry resolve low energy excitations, is a unique tool that can be used to assess nematic fluctuations and nematic ordering tendencies. Here, we compare results from determinant quantum Monte Carlo simulations of the Hubbar…
Optical and Raman spectroscopy studies on Fe-based superconductors
本文简要回顾了铁基超导体的光学和喇曼光谱研究，着重讨论了铁基超导体中的竞争现象。对ReFeAsO（Re=稀土元素）和AFe $_2$ As $_2$（A=碱土金属）族的光学研究表明，对称性破缺态中存在能隙，包括母体化合物自旋密度波态中的部分能隙和掺杂化合物超导态中的配对能隙.特别是空穴掺杂BaFe $_2$ As $_2$的超导能隙隙具有s波配对线形。对几种铁基化合物用拉曼和红外技术探测到的带心光学声子进行了分类。讨论了电子-声子耦合、自旋密度波和超导跃迁对声子的影响等问题。同时，还简要讨论了尚待解决的问题，包括\emph{T}依赖的0.6-0.7 eV的中红外峰、电子相关性以及高\Tc铜氧化物与铁基超导体的异同。从其他实验探针的重要结果与光学数据进行比较，以更好地理解自旋密度波的性质，超导电性，和多带字符在铁基化合物。
Raman scattering in cuprate oxychlorides high-temperature superconductors single-crystals
Karlsruhe Institute of Technology（卡尔斯鲁厄理工学院）；Institut NEEL CNRS/UGA UPR2940（NEEL研究所）；IMPMC-Sorbonne Universités, Université Pierre et Marie Curie, CNRS, IRD, MNHN（IMPMC-索邦大学，皮埃尔和玛丽·居里大学，CNRS，IRD，MNHN）；Synchrotron SOLEIL（SOLEIL同步辐射中心）；Department of Physics, University of Fribourg（弗里堡大学物理系）；Department of Materials Science, Graduate School of Engineering, Osaka Metropolitan University（大阪公立大学工学研究科材料科学系）
Raman-Scattering Detection of Nearly Degenerate $s$-Wave and $d$-Wave Pairing Channels in Iron-Based Ba$_{0.6}$K$_{0.4}$Fe$_2$As$_2$ and Rb$_{0.8}$Fe$_{1.6}$Se$_2$ Superconductors
我们表明，电子拉曼散射提供了一个窗口的铁基超导体的配对电位$V_{\mathbf{k},\mathbf{k^{\prime}}}$的基本属性。在Ba $_{0.6}$ K $_{0.4}$ Fe $_2$作为$_2$，我们观察到带相关的能隙随着激子Bardasis-Schrieffer模式的特征，分别占主导地位和次主导的配对通道。所有激子的$d_{x^2-y^2}$对称性使我们能够确定次优势通道起源于电子带之间的相互作用。因此，驱动超导性的主导通道是电子和空穴带之间相互作用的结果，并且具有完全的晶格对称性。Rb $_{0.8}$ Fe $_{1.6}$ Se $_2$的结果以及Ba（Fe $_{0.939}$ Co $_{0.061}$）$_2$ As $_2$的早期结果突出了费米表面拓扑对配对相互作用的影响。
The pressure dependence of electron-phonon coupling in the organic superconductor $κ$-(BEDT-TTF)$_{2}$Cu(SCN)$_{2}$: A comparison of high pressure infrared reflectivity and Raman scattering experiments
Both electronic Raman scattering (ERS) and angle-resolved photoemission spectra (ARPES) revealed two energy scales for the gap in different momentum spaces in the cuprates. However, the interpretations were different, and the gap values were also different in two experiments. In order to clarify the origin of these discrepancies, we directly compared ERS and ARPES by calculating ERS from the experimental data of ARPES through the Kubo formula. The calculated ERS spectra were in good agreement with the experimental results except for the B$_{1g}$ peak energies. The doping-dependent B$_{2g}$ pea…
Raman scattering near a d-wave Pomeranchuk instability
最近的运输和中子散射实验表明，在欠掺杂的铜氧化物的取向对称性破缺的动机，我们提出了一个理论研究的拉曼散射附近的d波波Pomeranchuk不稳定性（PI）。拉曼散射的d-波分量的电子和声子允许直接研究与PI相关的序参量波动。接近PI从正常状态，通过降低温度的中心峰出现在电子和，作为一个额外的低频功能，在声子散射。在低温超导态下，通过降低掺杂浓度来接近PI，中心峰被一个宽度和能量都大大减小、谱权增大的软模所取代。这些预测的低能量特征在拉曼散射可以确认在一个相当直接的方式存在的PI在高温铜酸盐超导体和Sr 3Ru 2 O 7。
