Charge and dielectric response to terahertz pulses in the charge-ordered phase of α?(BEDT?TTF)2I3
Charge and dielectric response to terahertz pulses in the charge-ordered phase of α?(BEDT?TTF)2I3
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α?(BEDT?TTF)2I3 电荷有序相中太赫兹脉冲的电荷和介电响应
DOI：
10.1103/physrevb.98.165149
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发表时间：
2018
影响因子：
3.7
通讯作者：
Takahashi Akira
中科院分区：
文献类型：
--
作者：
Kuniki Shinnosuke;Ohmura Shu;Takahashi Akira
我们研究了电荷有序相的介电性质，使用精确的数值计算的扩展Hubbard模型。电子对电荷有序基态的电极化（电子极化）P <$的贡献是通过直接计算当转移积分从对称积分转换为电荷有序相的积分而没有反转对称时的电流来获得的。P ′与正轴的夹角为，这与实验结果和前人基于密度泛函理论的理论结果一致。此外，我们数值计算了太赫兹（THz）脉冲激发诱导的动力学。当THz脉冲电场与P <$0方向基本相同时，THz脉冲引起的电子极化强度变化和电荷极化强度变化（反映电荷阶数的幅度）最大。这源于通过bondbeing占主导地位的电流和太赫兹脉冲激发的绝热流动中的电荷转移。这些结果再现了太赫兹脉冲诱导动力学的实验结果的重要特征。
We investigated the dielectric properties of the charge-ordered phase ofusing exact numerical calculations of an extended Hubbard model. The electronic contribution to the electric polarization (electronic polarization) P¯ of the charge-ordered ground state is obtained by directly calculating the current when transfer integrals were changed adiabatically from symmetric integrals to integrals for the charge-ordered phase without inversion symmetry. The angle of P¯ from the positiveaxis is, which is consistent with experimental results and previous theoretical results based on density-functional theory. Furthermore, we numerically calculated the dynamics induced by terahertz- (THz-) pulse excitation. Both the THz-pulse-induced variation of the electronic polarization magnitude and that of the charge disproportionation that shows the charge-order amplitude are largest when the electric field of the THz pulse and P¯ have almost the same direction. This originates from the charge transfer through bondbeing dominant in both the adiabatic flow of the current and the THz-pulse excitation. These results reproduce important features of the experimental results of THz-pulse-induced dynamics.