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arXiv 2206.03473cond-mat.mes-hall
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使用椭圆偏振光的工程Floquet拓扑相位

Engineering Floquet topological phases using elliptically polarized light

Ranjani Seshadri, Diptiman Sen

摘要:

研究了一个二维拓扑系统在椭圆偏振光作用下的动力学行为。特别是,我们分析了Bernevig-Hughes-Zhang模型,当它被扰动时,使用椭圆偏振光的频率$Ω$一般描述的矢量位${\bf A}(t) = (A_{0x} \cos(Ωt), A_{0y} \cos(Ωt + ϕ_0))$。(通过适当地选择$A_{0x}$、$A_{0y}$和$ϕ_0$,可以获得线性和圆偏振作为该一般形式的特殊情况)。即使对于固定值的$ϕ_0$,我们也可以通过改变驱动器的$x$和$y$组件的比率来改变系统的拓扑特征。因此,我们发现一个丰富的拓扑相图作为$A_{0x}$,$A_{0y}$和$ϕ_0$的函数。在这些阶段中的每一个中,由陈数给出的拓扑不变量与纳米粒子边缘处存在的自旋极化状态的数量一致。

英文摘要:

We study a two-dimensional topological system driven out of equilibrium by the application of elliptically polarized light. In particular, we analyze the Bernevig-Hughes-Zhang model when it is perturbed using an elliptically polarized light of frequency $Ω$ described in general by a vector potential ${\bf A}(t) = (A_{0x} \cos(Ωt), A_{0y} \cos(Ωt + ϕ_0))$. (Linear and circular polarizations can be obtained as special cases of this general form by appropriately choosing $A_{0x}$, $A_{0y}$, and $ϕ_0$). Even for a fixed value of $ϕ_0$, we can change the topological character of the system by changing the ratio of the $x$ and $y$ components of the drive. We therefore find a rich topological phase diagram as a function of $A_{0x}$, $A_{0y}$ and $ϕ_0$. In each of these phases, the topological invariant given by the Chern number is consistent with the number of spin-polarized states present at the edges of a nanoribbon.

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