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A Unification of the Holstein Polaron and Dynamic Disorder Pictures of Charge Transport in Organic Crystals
Physical Review X ( IF 12.5 ) Pub Date : 2020-06-17 , DOI: 10.1103/physrevx.10.021062
Jonathan H. Fetherolf , Denis Golež , Timothy C. Berkelbach

We present a unified and nonperturbative method for calculating spectral and transport properties of Hamiltonians with simultaneous Holstein (diagonal) and Peierls (off-diagonal) electron-phonon coupling. Our approach is motivated by the separation of energy scales in organic molecular crystals, in which electrons couple to high-frequency intramolecular Holstein modes and to low-frequency intermolecular Peierls modes. We treat Peierls modes as quasiclassical dynamic disorder, while Holstein modes are included with a Lang-Firsov polaron transformation and no narrow-band approximation. Our method reduces to the popular polaron picture due to Holstein coupling and the dynamic disorder picture due to Peierls coupling. We derive an expression for efficient numerical evaluation of the frequency-resolved optical conductivity based on the Kubo formula and obtain the dc mobility from its zero-frequency component. We also use our method to calculate the electron-addition Green’s function corresponding to the inverse photoemission spectrum. For realistic parameters, temperature-dependent dc mobility is largely determined by the Peierls-induced dynamic disorder with minor quantitative corrections due to polaronic band narrowing, and an activated regime is not observed at relevant temperatures. In contrast, for frequency-resolved observables, a quantum-mechanical treatment of the Holstein coupling is qualitatively important for capturing the phonon replica satellite structure.

中文翻译:

荷斯坦极化子和有机晶体中电荷传输的动态无序图的统一

我们提出了一种统一且非摄动的方法,用于同时计算荷斯坦(对角线)和皮尔斯(非对角线)电子-声子耦合,计算哈密顿量的光谱和传输性质。我们的方法是由有机分子晶体中能级的分离激发的,其中电子耦合到高频分子内霍尔斯坦模和低频分子间Peierls模式。我们将Peierls模式视为准经典动态障碍,而Holstein模式包含在Lang-Firsov极化子变换中并且没有窄带近似。我们的方法归因于Holstein耦合而简化为流行的极化子图,而归因于Peierls耦合而简化为动态无序图。我们基于久保公式推导了一个有效数值评估频率分辨光导率的表达式,并从其零频分量获得了直流迁移率。我们还使用我们的方法来计算对应于反向光发射光谱的加电子格林函数。对于实际参数,取决于温度的直流迁移率主要由Peierls引起的动态无序确定,由于极化子带变窄,因此进行了较小的定量校正,并且在相关温度下未观察到激活状态。相反,对于频率分辨的可观测物,荷斯坦耦合的量子力学处理对于捕获声子复制卫星结构在质量上很重要。我们还使用我们的方法来计算对应于反向光发射光谱的加电子格林函数。对于实际参数,取决于温度的直流迁移率主要由Peierls引起的动态无序确定,由于极化子带变窄,因此进行了较小的定量校正,并且在相关温度下未观察到激活状态。相反,对于频率分辨的可观测物,荷斯坦耦合的量子力学处理对于捕获声子复制卫星结构在质量上很重要。我们还使用我们的方法来计算对应于反向光发射光谱的加电子格林函数。对于实际参数,取决于温度的直流迁移率主要由Peierls引起的动态无序确定,由于极化子带变窄,因此进行了较小的定量校正,并且在相关温度下未观察到激活状态。相反,对于频率分辨的可观测物,荷斯坦耦合的量子力学处理对于捕获声子复制卫星结构在质量上很重要。并且在相关温度下未观察到激活状态。相反,对于频率分辨的可观测物,荷斯坦耦合的量子力学处理对于捕获声子复制卫星结构在质量上很重要。并且在相关温度下未观察到激活状态。相反,对于频率分辨的可观测物,荷斯坦耦合的量子力学处理对于捕获声子复制卫星结构在质量上很重要。
更新日期:2020-06-17
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