论文标题
在三轨哈伯德模型中光诱导的伪旋转极化
Photoinduced Pseudospin Polarization in a Three-Orbital Hubbard Model
论文作者
论文摘要
在Kitaev旋转液体候选材料的Hubbard模型中，每个RU站点的三个$ t_ {2g} $ orbitals $α$ -rucl $ _3 $，我们根据精确的对角化方法来计算光诱导的动态，并在Quantum Floquet理论中的高频扩展中解释它们。高频扩展在应用圆极化光场期间显示了两种类型的有效磁场。其中一个源自自旋轨道耦合，并在蜂窝晶格内。另一个纯粹是动力学的，垂直于晶格。以前的磁场在一个单位电池内的两个位点是反平行的，并按照沿光场的孔的动量分布旋转。当光场很弱时，伪一种动力学由以前的田地支配。因此，伪辛的平均值几乎消失了。后一个磁场在单位单元格内的两个位点平行，当光场很强时产生伪辛的非零垂直成分。当光场的频率远低于mott GAP时，数值获得的垂直组件与后一个场一致。讨论了最近在$α$ -rucl $ _3 $中观察到的与Faraday倒数效应的相关性。
In a Hubbard model for the Kitaev spin-liquid candidate material $α$-RuCl$_3$ with three $t_{2g}$ orbitals per Ru site, we calculate photoinduced dynamics based on the exact diagonalization method and interpret them with the help of a high-frequency expansion in quantum Floquet theory. The high-frequency expansion shows two types of effective magnetic fields during the application of a circularly polarized light field. One of them originates from spin-orbit coupling and is within the honeycomb lattice. The other is of purely kinetic origin and perpendicular to the lattice. The former fields are antiparallel at the two sites within a unit cell and rotate in accordance with the momentum distribution of holes that follow the light field. When the light field is weak, pseudospin dynamics are governed by the former fields; thus, the average of the pseudospins almost vanishes. The latter fields are parallel at the two sites within a unit cell and produce nonzero perpendicular components of the pseudospins when the light field is strong. Numerically obtained perpendicular components are consistent with the latter fields when the frequency of the light field is well below the Mott gap. The relevance to the inverse Faraday effect recently observed in $α$-RuCl$_3$ is discussed.
