Puviani M, Baum A, Ono S, Ando Y, Hackl R, Manske D
Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany.
Walther Meissner Institut, Bayerische Akademie der Wissenschaften, 85748 Garching, Germany.
Phys Rev Lett. 2021 Nov 5;127(19):197001. doi: 10.1103/PhysRevLett.127.197001.
In superconductors the Anderson-Higgs mechanism allows for the existence of a collective amplitude (Higgs) mode which can couple to eV light mainly in a nonlinear Raman-like process. The experimental nonequilibrium results on isotropic superconductors have been explained going beyond the BCS theory including the Higgs mode. Furthermore, in anisotropic d-wave superconductors strong interaction effects with other modes are expected. Here we calculate the Raman contribution of the Higgs mode from a new perspective, including many-body Higgs oscillations effects and their consequences in conventional, spontaneous Raman spectroscopy. Our results suggest a significant contribution to the intensity of the A_{1g} symmetry Raman spectrum in d-wave superconductors. In order to test our theory, we predict the presence of measurable characteristic oscillations in THz quench-optical probe time-dependent reflectivity experiments.
在超导体中，安德森 - 希格斯机制允许存在一种集体振幅（希格斯）模式，该模式主要能在类似非线性拉曼的过程中与电子伏特量级的光发生耦合。关于各向同性超导体的非平衡实验结果，已在超越包含希格斯模式的BCS理论的框架下得到了解释。此外，在各向异性的d波超导体中，预计会出现与其他模式的强相互作用效应。在此，我们从一个新的视角计算希格斯模式的拉曼贡献，包括多体希格斯振荡效应及其在传统自发拉曼光谱中的结果。我们的结果表明，这对d波超导体中A₁g对称拉曼光谱的强度有显著贡献。为了检验我们的理论，我们预测在太赫兹猝灭 - 光学探针时间相关反射率实验中会出现可测量的特征振荡。
