1. Inroduction Results Conclusion
Quantum Anomalous Hall Effect in Stanene
on a Nonmagnetic Substrate
Huisheng Zhang, Tong Zhou, Jiayong Zhang, and Zhongqin Yang*
Department of Physics, Fudan University, Shanghai , China
Inroduction
The quantum anomalous Hall (QAH) effect, in which the bulk state is insulating while exhibiting unique chiral edge states in the absence of external magnetic field, has been realized in magnetic topological insulator (TI) films of Cr doped (Bi,Sb)2Te3 films. The experimental observation of the QAH effect is not only a milestone discovery for searching novel topological states and developing low power consumption electronic devices, but also has great advancements in condensed matter physics and material science. The realizing requirements of the effect in the experiments, however, are usually very harsh, disadvantageous to the practical applications. For example, the temperature for observing this effect is extremely low (dozens of mK). Novel systems with QAH effects, accessible in experiments, are in much demand.
FIG. 3. (a) FM and 120° AFM orders considered for the SnH/PbI2 heterostructure. (b) Band structures for the SnH/PbI2 heterostructure with SOC by using DFT methods and Wannier interpretation. (c) The corresponding distribution of Berry curvature in the 2D momentum space. (d) The electric field effect on the band gap of the heterostructure.
Results
FIG. 4. (a) The PbI2/SnH/PbI2 sandwiched heterostructure. (b) Band structures for the PbI2/SnH/PbI2 sandwiched heterostructure with SOC by using DFT methods and Wannier interpretation. (c,d) The schematic diagrams to realize the QAH effect in SnH/PbI2 heterostructures and PbI2/SnH/PbI2 sandwiched heterostructures, respectively.
FIG. 1. (a) Total energy of the PbI2 monolayer as a function of the lattice constant. Side (b) and top (c) views of half-H-passivated stanene grown on the PbI2 monolayer.
Conclusion
We systematically investigated the electronic and topological properties of honeycomb stanene placed on PbI2 films. The results show that the QAH effect can be achieved in the half-hydrogen (halogen)-passivated Sn/PbI2 heterostructure. The nontrivial band gap can be up to 90 meV, much larger than the usual QAH systems reported previously. The obtained non-vanishing Chern number (C = 1) indicates the insulating state in the system is topologically nontrivial. Our work indicates that robust QAH effects with pretty large gaps can be realized relatively straightforward in these proposed heterostructures in experiments.
FIG. 2. The band structures of the SnH/PbI2 heterostructure (a) without and (b) with SOC.