论文标题
不WIST的Moiré物理学:几乎理想的带和分数Chern绝缘子在周期性紧张的单层石墨烯中
Untwisting moiré physics: Almost ideal bands and fractional Chern insulators in periodically strained monolayer graphene
论文作者
论文摘要
近年来,MoiréSystems已成为研究牢固相关性的丰富平台。在这里,我们将讨论基于周期性紧张的石墨烯的简单,实验可行的设置,该设置再现了扭曲的Moiré异质结构的几个关键方面 - 但没有引入扭曲。我们考虑一个单层石墨烯片,约有$ C_2 $的周期性应变诱导的伪磁磁场(PMF),带有$ l_m \ gg a $,以及同一时期的标量潜力。该系统具有{\ IT几乎是理想}的平面带,带有山谷分辨的Chern Number $ \ pm 1 $,在分析中,与理想带的几何形状的偏差在分析中受到分析,并且在无尺寸的比率$ $(l_m/l_b)中呈指数较小(l_m/l_b)^2 $,其中$ l_b $的磁性长度与磁性长度相对应的最大值是PMF的最大值。此外,标量电势可以将带宽远低于库仑量表,这使其成为强烈相互作用的拓扑阶段的非常有前途的平台。通过结合强耦合理论和自洽的Hartree Fock,我们在整数填充物中发现了量子异常的霍尔态。在分数填充时,精确的对角线会在实验可行范围内的参数显示一个分数Chern绝缘子。总体而言,我们发现该系统具有较大的相互作用诱导的差距,较小的准粒子分散体以及与扭曲石墨烯系统相比,即使在其理想极限处也相比。
Moiré systems have emerged in recent years as a rich platform to study strong correlations. Here, we will discuss a simple, experimentally feasible setup based on periodically strained graphene that reproduces several key aspects of twisted moiré heterostructures -- but without introducing a twist. We consider a monolayer graphene sheet subject to a $C_2$-breaking periodic strain-induced psuedomagnetic field (PMF) with period $L_M \gg a$, along with a scalar potential of the same period. This system has {\it almost ideal} flat bands with valley-resolved Chern number $\pm 1$, where the deviation from ideal band geometry is analytically controlled and exponentially small in the dimensionless ratio $(L_M/l_B)^2$ where $l_B$ is the magnetic length corresponding to the maximum value of the PMF. Moreover, the scalar potential can tune the bandwidth far below the Coulomb scale, making this a very promising platform for strongly interacting topological phases. Using a combination of strong-coupling theory and self-consistent Hartree fock, we find quantum anomalous Hall states at integer fillings. At fractional filling, exact diagonaliztion reveals a fractional Chern insulator at parameters in the experimentally feasible range. Overall, we find that this system has larger interaction-induced gaps, smaller quasiparticle dispersion, and enhanced tunability compared to twisted graphene systems, even in their ideal limit.