论文标题
非平衡谷极化量子异常效果的浮quet工程和可调的Chern编号
Floquet Engineering of Nonequilibrium Valley-Polarized Quantum Anomalous Hall Effect with Tunable Chern Number
论文作者
论文摘要
到目前为止，已经进行了许多尝试来探索量子异常效应（QAHE），但是超高的观察到的温度极大地阻碍了其实际应用。因此，超越Qahe的现有范式是极大的兴趣。在这里，我们建议Floquet Engineering提供了一种通过Floquet-Bloch频段杂交实现Qahe的策略。基于第一原则的计算和浮点定理，我们公布了非平衡谷极化的Qahe（VP-QAHE），独立于磁性订单，在铁磁和非磁性中广泛存在于二维家庭材料的二维家庭材料的成员中圆极化光（CPL）。值得注意的是，通过调整入射CPL的频率，强度和惯用性，VP-QAHE的Chern数量高度可调，最多可达$ \ MATHCAL {C} = \ PM 4 $。我们揭示了这种Chern数字可调vp-qahe归因于光引起的三角形翘曲和不同山谷的多个带反转。在全球频带间隙内可见，可促进实验测量的山谷分辨的手性边缘状态和量化霍尔电导的高原。我们的作品不仅建立了具有逼真材料中可调的Chern号的非平衡VP-QAHE的浮点工程，而且还提供了一种有希望的途径，可以在光照射下探索新兴的拓扑阶段。
Numerous attempts have been made so far to explore the quantum anomalous Hall effect (QAHE), but the ultralow observed temperature strongly hinders its practical applications. Hence, it is of great interest to go beyond the existing paradigm of QAHE. Here, we propose that Floquet engineering offers a strategy to realize the QAHE via hybridization of Floquet-Bloch bands. Based on first-principles calculations and Floquet theorem, we unveil that nonequilibrium valley-polarized QAHE (VP-QAHE), independent of magnetic orders, is widely present in ferromagnetic and nonmagnetic members of two-dimensional family materials $M$Si$_2$$Z_4$ ($M$ = Mo, W, V; $Z$ = N, P, As) by irradiating circularly polarized light (CPL). Remarkably, by tuning the frequency, intensity, and handedness of incident CPL, the Chern number of VP-QAHE is highly tunable and up to $\mathcal{C}=\pm 4$. We reveal that such Chern number tunable VP-QAHE attributes to light-induced trigonal warping and multiple band inversion at different valleys. The valley-resolved chiral edge states and quantized plateau of Hall conductance, which facilitates the experimental measurement, are visible inside the global band gap. Our work not only establishes Floquet Engineering of nonequilibrium VP-QAHE with tunable Chern number in realistic materials, but also provides a promising avenue to explore emergent topological phases under light irradiation.
