论文标题
激子绝缘子中集体模式的非线性光谱
Nonlinear spectroscopy of collective modes in excitonic insulator
论文作者
论文摘要
证明与晶格自由度耦合的激子绝缘子的非线性光学响应证明，具有强大和特征的方式取决于绝缘行为是主要来自电子电子还是电子驻线相互作用。确定了巨大相位模式和振幅（HIGGS）模式的线性响应光学签名。在非线性激发与相位模式共鸣时，诱导相位模式频率的新缝隙模式是两倍，从而导致了巨大的第二次谐波响应。内置声子模式的激发会导致不同的和较小的效果。 Landau-Ginzburg理论分析解释了这些不同的行为，并揭示了强烈激发相模式的参数共振是在电子优先情况下光诱导模式的起源。非线性光学响应的差异是对有序阶段的主要机制的度量。
The nonlinear optical response of an excitonic insulator coupled to lattice degrees of freedom is shown to depend in strong and characteristic ways on whether the insulating behavior originates primarily from electron-electron or electron-lattice interactions. Linear response optical signatures of the massive phase mode and the amplitude (Higgs) mode are identified. Upon nonlinear excitation resonant to the phase mode, a new in-gap mode at twice the phase mode frequency is induced, leading to a huge second harmonic response. Excitation of in-gap phonon modes leads to different and much smaller effects. A Landau-Ginzburg theory analysis explain these different behavior and reveals that a parametric resonance of the strongly excited phase mode is the origin of the photo-induced mode in the electron-dominant case. The difference in the nonlinear optical response serve as a measure of the dominant mechanism of the ordered phase.
