论文标题
魔术角石墨烯在过渡金属二甲化合物上的平坦带拓扑
Flat band topology of magic angle graphene on a transition metal dichalcogenide
论文作者
论文摘要
我们考虑在过渡金属二进制基质底物上扭曲的双层石墨烯，在该金属二进制基质底物上，接近性诱导的自旋轨道耦合显着改变了八个在魔术角附近发生的平坦频带。所得的带结构在大多数迷你奶油区域中具有一对极平坦的频带。更多细节敏感地取决于异质结构的对称性。当围绕平面内轴的所有两倍旋转被打破时，我们发现半导体带结构，而半金属的条带结构则否则。我们计算了不同孤立带的Chern数字，并确定了谷谷雪烧绝缘子和拓扑绝缘子的实现的参数制度和填充因子。有趣的是，我们发现，对于接近性诱导的术语的现实值，可以通过将每个超级峰值单元池掺入两个孔或两个电子，从而实现受时间反转对称性保护的拓扑绝缘子。
We consider twisted bilayer graphene on a transition metal dichalcogenide substrate, where proximity-induced spin-orbit coupling significantly alters the eight flat bands which occur near the magic angle. The resulting band structure features a pair of extremely flat bands across most of the mini-Brillouin zone. Further details depend sensitively on the symmetries of the heterostructure; we find semiconducting band structures when all two-fold rotations around in-plane axis are broken, and semi-metallic band structures otherwise. We calculate the Chern numbers of the different isolated bands, and identify the parameter regimes and filling factors where valley Chern insulators and topological insulators are realized. Interestingly, we find that for realistic values of the proximity-induced terms, it is possible to realize a topological insulator protected by time-reversal symmetry by doping two holes or two electrons per superlattice unit cell into the system.
