Kwan Yves H, Hu Yichen, Simon Steven H, Parameswaran S A
Rudolf Peierls Centre for Theoretical Physics, Clarendon Laboratory, Oxford OX1 3PU, United Kingdom.
Phys Rev Lett. 2021 Apr 2;126(13):137601. doi: 10.1103/PhysRevLett.126.137601.
We uncover topological features of neutral particle-hole pair excitations of correlated quantum anomalous Hall (QAH) insulators whose approximately flat conduction and valence bands have equal and opposite nonzero Chern number. Using an exactly solvable model we show that the underlying band topology affects both the center-of-mass and relative motion of particle-hole bound states. This leads to the formation of topological exciton bands whose features are robust to nonuniformity of both the dispersion and the Berry curvature. We apply these ideas to recently reported broken-symmetry spontaneous QAH insulators in substrate aligned magic-angle twisted bilayer graphene.
我们揭示了具有近似平坦的导带和价带且具有相等且相反的非零陈数的关联量子反常霍尔（QAH）绝缘体的中性粒子 - 空穴对激发的拓扑特征。通过一个精确可解模型，我们表明底层能带拓扑影响粒子 - 空穴束缚态的质心运动和相对运动。这导致了拓扑激子带的形成，其特征对于色散和贝里曲率的不均匀性具有鲁棒性。我们将这些想法应用于最近报道的在衬底对齐的魔角扭曲双层石墨烯中的破缺对称自发QAH绝缘体。
