Non-Collinear Orbital-induced Planar Quantum Anomalous Hall Effect.

Based on the 2D star lattice with noncollinear orbital, we present an intriguing six-band tight-binding model for planar quantum anomalous Hall effect (PQAHE) with in-plane magnetization. Depending on the orientation of the noncollinear orbital, the characterized Dirac-, Kagome-, and Four-band are all realizable. Moreover, including the intrinsic spin-orbital coupling, a topological phase diagram versus angle of both in-plane magnetization and noncollinear orbital is mapped out, showing a tunable PQAHE with Chern number of either +1 or -1. Most remarkably, using first-principles calculations, this exact model of PQAHE is identified in an experimentally synthesized 2D metal-organic framework (MOF) of Pr2(C6O4Cl2)3. These notable results not only demonstrate the significance of noncollinear orbital for designing PQAHE but also provide a MOF platform for its realization, greatly enriching the fundamental topological physics and extending the candidate topological materials.