论文标题
堆叠引起的Chern绝缘子
Stacking-induced Chern insulator
论文作者
论文摘要
像修改的haldane模型一样，可以通过添加依赖山谷依赖的伪量表电位来将石墨烯转变为半分的，具有破碎的时间反转对称性，该伪量表势将Dirac点能量转移到相反的方向上。我们考虑通过堆叠修改后的Haldane模型的两个时间转换的副本获得的双层，其中传导和价带交叉在每个山谷中产生一个淋巴结线。在AB堆叠中，层中的层跳提升了节点线的堕落并引起乐队的排斥力，令人惊讶地导致了带有Chern Number $ C = \ pm2 $的手性绝缘体。结果，一对手性边缘状态出现在色带双层几何形状的边界处。相反，AA堆叠并未显示出非平凡的拓扑阶段。我们讨论了结果的可能实现。
Graphene can be turned into a semimetal with broken time-reversal symmetry by adding a valley-dependent pseudo-scalar potential that shifts the Dirac point energies in opposite directions, as in the modified Haldane model. We consider a bilayer obtained by stacking two time-reversed copies of the modified Haldane model, where conduction and valence bands cross to give rise to a nodal line in each valleys. In the AB stacking, the interlayer hopping lifts the degeneracy of the nodal lines and induces a band repulsion, leading surprisingly to a chiral insulator with a Chern number $C=\pm2$. As a consequence a pair of chiral edge states appears at the boundaries of the ribbon bilayer geometry. In contrast, the AA stacking does not show nontrivial topological phases. We discuss possible experimental implementations of our results.
