论文标题
耦合到Anharmonic声子的电导率
Conductivity of an electron coupled to anharmonic phonons
论文作者
论文摘要
我们使用非视扰动量子古典方法研究了声子非谐度对软材料的电子动力学的影响。该方法应用于具有低频间分子晶格声子的掺杂有机半导体的一维模型。我们发现导致声子硬化的非谐调会增加导致声子软化的迁移率和非谐度，从而降低了迁移率。我们还测试了各种近似值，包括使用绝热声子障碍，具有温度依赖性频率的有效谐波模型以及具有二阶扰动理论散射速率的玻尔兹曼传输方程。总体而言，我们发现所有方法之间令人惊讶的是良好的一致性，但是对声子非谐度的核算对于精确预测电子传输至关重要，包括定量迁移率值及其定性温度依赖性。对于所研究的模型，声子寿命效应对载体的传输的影响相对较小，但是由于非谐度而导致的有效频移是必不可少的。在高度不对称，非高斯疾病的情况下，有效的谐波模型不能定量再现迁移率或有限频率的电导率，而对于声音声子尤其如此。
We study the impact of phonon anharmonicity on the electronic dynamics of soft materials using a nonperturbative quantum-classical approach. The method is applied to a one-dimensional model of doped organic semiconductors with low-frequency intermolecular lattice phonons. We find that anharmonicity that leads to phonon hardening increases the mobility and anharmonicity that leads to phonon softening decreases the mobility. We also test various approximations, including the use of adiabatic phonon disorder, an effective harmonic model with temperature-dependent frequencies, and the Boltzmann transport equation with second-order perturbation theory scattering rates. Overall, we find surprisingly good agreement between all methods but that accounting for phonon anharmonicity is important for accurate prediction of electronic transport including both quantitative mobility values and their qualitative temperature dependence. For the model studied, phonon lifetime effects have relatively little impact on carrier transport, but the effective frequency shift due to anharmonicity is essential. In cases with highly asymmetric, non-Gaussian disorder, an effective harmonic model cannot quantitatively reproduce mobilities or finite-frequency conductivity, and this is especially true for acoustic phonons.
