论文标题
薄膜磁性拓扑绝缘子的扭曲双层
Twisted bilayers of thin film magnetic topological insulators
论文作者
论文摘要
“魔术角”附近的扭曲的双层石墨烯（TBG）已成为一个丰富的平台，用于二维狄拉克半学的密切相关状态。在这里，我们表明薄膜磁性绝缘子（MTI）具有较大的平面磁化强度的扭曲双层可以实现2D DIRAC节点附近的平坦带。使用用于MTIS薄膜的简单模型，我们得出了两个这样的MTI的连续模型，相互相对于彼此而被一个小角度扭曲。当磁力化为内部时，我们表明层间隧道术语充当有效的$ SU（2）$向量电位，众所周知，这会导致TBG的平坦频段。我们表明，通过更改平面磁化强度，可以将扭曲的双层MTI频带分散调整为二次带触摸或与TBG相似的平面带。如果实现的话，该系统可能是一个高度可调的平台，用于二维Dirac半学阶段的强相关阶段。
Twisted bilayer graphene (TBG) near "magic angles" has emerged as a rich platform for strongly correlated states of two-dimensional Dirac semimetals. Here we show that twisted bilayers of thin-film magnetic topological insulators (MTI) with large in-plane magnetization can realize flat bands near 2D Dirac nodes. Using a simple model for thin films of MTIs, we derive a continuum model for two such MTIs, twisted by a small angle with respect to each other. When the magnetization is in-plane, we show that interlayer tunneling terms act as effective $SU(2)$ vector potentials, which are known to lead to flat bands in TBG. We show that by changing the in-plane magnetization, it is possible to tune the twisted bilayer MTI band dispersion to quadratic band touching or to flat bands, similar to the TBG. If realized, this system can be a highly tunable platform for strongly correlated phases of two-dimensional Dirac semimetals.
