标题： 反对称拉曼响应 显示英文标题

标题： Antisymmetric Raman response

摘要： 我们发展了反称拉曼响应的理论，该理论定义为两个散射几何配置之间的拉曼信号差，这两个配置通过入射和出射光子偏振的交换相关联。 这种响应在正交或更低对称性系统中是有限的，与两个拉曼算符的交叉极化率有关，并且以缺乏带内项为特征。 这与标准拉曼响应形成对比，后者测量的是自极化率，其中带内和带间过程都有贡献。 我们通过电荷密度波稀土三碲化物和激子绝缘体 Ta$_2$NiSe$_5$的例子来说明这一理论。 我们的理论确立了反称拉曼响应作为一种独特的工具，用于探测微观特性，如带间能量尺度，并检测反射对称性破缺。 显示英文摘要

摘要： We develop the theory of antisymmetric Raman response, defined as the difference between the Raman signals of two scattering geometries related by an exchange of mutually perpendicular incoming and the outgoing photon polarizations. Such responses, finite in orthorhombic or lower symmetry systems, are related to cross-susceptibilities of two Raman operators and are characterized by the absence of intraband terms. This is in contrast to standard Raman responses which measure auto-susceptibilities where both intra- and interband processes contribute. We illustrate the theory with examples from the charge density wave rare-earth tritellurides and the excitonic insulator Ta$_2$NiSe$_5$. Our theory establishes antisymmetric Raman response as a unique tool to probe microscopic features such as interband energy scales and to detect reflection symmetry breaking.