Intrinsic quantum anomalous Hall phase induced by proximity in the van der Waals heterostructure germanene/Cr2Ge2Te6

A van der Waals heterostructure combined with intrinsic magnetism and topological orders have recently paved attractive avenues to realize quantum anomalous Hall effects. In this work, using first-principles calculations and effective model analysis, we propose that the robust quantum anomalous Hall states with sizable band gaps emerge in the van der Waals heterostructure of germanene/Cr2Ge2Te6. This heterostructure possesses high thermodynamic stability, thus facilitating its experimental fabrication. Furthermore, we uncover that the proximity effect enhances the coupling between the germanene and Cr2Ge2Te6 layers, inducing the nontrivial band gaps in a wide range from 29 to 72 meV. The chiral edge states inside the band gap, leading to Hall conductance quantized to -e(2)/h, are clearly visible. These findings provide an ideal candidate to detect the quantum anomalous Hall states and realize further applications to nontrivial quantum transport at a high temperature.