论文标题
在声子调味料下的非线性非年代光电
Nonlinear Nonreciprocal Photocurrents under Phonon Dressing
论文作者
论文摘要
非线性光学（NLO）效应最近引起了极大的兴趣。但是，到目前为止，关于NLO的计算研究使用独立的粒子近似并忽略了多体效应。在这里，我们开发了一个通用的绿色功能框架来计算NLO响应函数，该函数可以结合各种多体相互作用。我们专注于电子 - 音波耦合，并揭示了声子敷料可以对非线性光电流产生重大影响，例如散装光伏（BPV）和大量的自旋光伏电动汽车（BSPV）电流。中心对称晶体的BPV/BSPV应为零，但是当声子被驱动到平衡外时，例如，温度梯度$ \ nabla t $，光学选择规则会被更改，并且在名义中心的中心合成中，可以更改phitolon pump pumpv/bspv courtrent。此外，我们阐明，在非平衡声子敷料下的这种NLO反应可能是非偏置的，因为当温度梯度的方向逆转时，电流的方向不一定会逆转。
Nonlinear optical (NLO) effects have attracted great interest recently. However, by far the computational studies on NLO use the independent particle approximation and ignore many-body effects. Here we develop a generic Green's function framework to calculate the NLO response functions, which can incorporate various many-body interactions. We focus on the electron-phonon coupling and reveal that phonon dressing can make significant impacts on nonlinear photocurrent, such as the bulk photovoltaic (BPV) and bulk spin photovoltaic (BSPV) currents. BPV/BSPV should be zero for centrosymmetric crystals, but when phonons are driven out-of-equilibrium, by for example, a temperature gradient $\nabla T$, the optical selections rules are altered and phonon-pumped BPV/BSPV currents can be non-zero in nominally centrosymmetric crystal. Moreover, we elucidate that such NLO responses under non-equilibrium phonon dressing can be nonreciprocal, as the direction of the current does not necessarily get reversed when the direction of the temperature gradient is reversed.
