论文标题
合成双层的量子异常霍尔阶段通过无扭曲
Quantum anomalous Hall phase in synthetic bilayers via twistless twistronics
论文作者
论文摘要
我们最近提出了基于超低原子和合成二维的“二散发性”物理学的量子模拟器[Phys。莱特牧师。 125，030504（2020）]。从概念上讲，该方案基于这样的观点，即通过识别具有合成空间维度的被困原子的内部状态，将所需几何形状的分解单层光学晶格升级到合成双层系统。内部国家之间的耦合，即两个层上的位点之间的耦合，可以通过激光诱导的拉曼过渡精确控制。通过空间调节层间耦合，可以直接在latticeCe上直接印记在层的物理扭转上。该方案实际上导致了整个Thelattice的均匀图案，其附加优势是可调的层间耦合强度。后者的特征促进了比常规旋转材料在较大的“魔法”角度或更直接的较小单位单元的工程设计。在本文中，我们扩展了这些想法，并证明我们的系统在适当条件下表现出拓扑结构。为了实现非平凡的带拓扑结构，我们考虑将系统驱动到量子异常的霍尔阶段的imanaginarynext到最新的邻居隧道。特别是，我们专注于三组频段，它们的Chern数字三重态可以与微不足道的绝缘子（0,0,0），标准的非平地（-1,0,1）和非标准的非平凡（-1,1,0）相关联。我们确定这三个情况发生的参数制度。我们显示了一个异常的霍尔阶段和观察边缘状态的存在。我们的作品为无需ATWIST的互助术的拓扑效应提供了实验的道路
We recently proposed quantum simulators of "twistronic-like" physics based on ultracold atoms and syntheticdimensions [Phys. Rev. Lett. 125, 030504 (2020)]. Conceptually, the scheme is based on the idea that aphysical monolayer optical lattice of desired geometry is upgraded to a synthetic bilayer system by identifyingthe internal states of the trapped atoms with synthetic spatial dimensions. The couplings between the internalstates, i.e. between sites on the two layers, can be exquisitely controlled by laser induced Raman transitions.By spatially modulating the interlayer coupling, Moiré-like patterns can be directly imprinted on the latticewithout the need of a physical twist of the layers. This scheme leads practically to a uniform pattern across thelattice with the added advantage of widely tunable interlayer coupling strengths. The latter feature facilitates theengineering of flat bands at larger "magic" angles, or more directly, for smaller unit cells than in conventionaltwisted materials. In this paper we extend these ideas and demonstrate that our system exhibits topologicalband structures under appropriate conditions. To achieve non-trivial band topology we consider imanaginarynext-to-nearest neighbor tunnelings that drive the system into a quantum anomalous Hall phase. In particular,we focus on three groups of bands, whose their Chern numbers triplet can be associated to a trivial insulator(0,0,0), a standard non-trivial (-1,0,1) and a non-standard non-trivial (-1,1,0). We identify regimes of parameterswhere these three situations occur. We show the presence of an anomalous Hall phase and the appearance oftopological edge states. Our works open the path for experiments on topological effects in twistronics without atwist
