论文标题
在一维延长的PEIERLS-HUBBARD模型中，光诱导的域内动力学和非电流状态的非热转换
Photoinduced intradomain dynamics and nonthermal switching of metastable states in the one-dimensional extended Peierls-Hubbard model
论文作者
论文摘要
我们通过精确的对角线化研究了四硫酸盐 - $ p $氯化的光诱导相变的初始阶段的微观动力学。我们首先表明，一维扩展的PEIERLS-HUBBARD模型表现出具有较小的离子性和可忽略不计的二聚体和具有中等离子性和二聚体的离子相的中性相。除了这些阶段，我们还发现了一个双电离阶段，具有强大的二聚化，我们称为“偶极子”阶段。这些地面阶段的特征是各种阶参数和ZAK相，这与电子极化有关。我们进一步探讨了由短单核细胞光学脉冲触发的三个相的微观动力学。电子阶参数和晶格位移表明中性离子，离子中性和偶极子离子转变被诱导。此外，在时间依赖的光谱密度和泵探针电导率中观察到明显的光谱变化。光谱法的详细分析表明，通过多光子吸收和激发态的关键作用以及超快动力学的新晶格位置产生了连贯的电荷转移字符串。
We investigate the microscopic dynamics at the initial stage of photoinduced phase transitions in tetrathiafulvalene-$p$-chloranil by exact diagonalization. We first show that the one-dimensional extended Peierls-Hubbard model exhibits a neutral phase with small ionicity and negligible dimerization and an ionic phase with moderate ionicity and dimerization. Aside from these phases, we find a doubly ionized phase with strong dimerization that we call the "dipole" phase. These ground-state phases are characterized by various order parameters and the Zak phase, which is relevant to electronic polarization. We further explore the microscopic dynamics of the three phases triggered by short monocycle optical pulses. The electronic order parameters and lattice displacement suggest that the neutral-ionic, ionic-neutral, and dipole-ionic transitions are induced. Furthermore, clear spectroscopic changes are observed in the time-dependent spectral density and pump-probe conductivity. A detailed analysis of the spectroscopy demonstrates the generation of coherent charge-transfer strings via multiphoton absorption and the crucial roles of the excited states and the metastable ground state at the new lattice position for the ultrafast dynamics.
