In-plane magnetization-induced quantum anomalous Hall effect in atomic crystals of group-V elements

Abstract

We theoretically demonstrate that the in-plane magnetization induced quantum anomalous Hall effect (QAHE) can be realized in atomic crystal layers of group-V elements with buckled honeycomb lattice. We first construct a general tight-binding Hamiltonian with sp 3 orbitals via Slater-Koster two-center approximation, and then numerically show that for weak and strong spin-orbit couplings the systems harbor QAHEs with Chern numbers of C = ±1 and ±2 , respectively. For the C = ±1 phases, we find the critical phase-transition magnetization from a trivial insulator to QAHE can become extremely small by tuning the spin-orbit coupling strength. Although the resulting band gap is small, it can be remarkably enhanced by orders via tilting the magnetization slightly away from the in-plane orientation. For the C = ±2 phases, we find that the band gap is large enough for the room-temperature observation. Although the critical magnetization is relatively large, it can be effectively decreased by applying a strain. All these suggest that it is experimentally feasible to realize high-temperature QAHE from in-plane magnetization in atomic crystal layers of group-V elements.

Chiral Majorana fermions in graphene from proximity-induced superconductivity

“…We present only results for uniform exchange coupling since for staggered exchange not all degeneracies are removed and we cannot easily calculate Chern numbers. The QAHE phase has been proposed to exist in low buckled honeycomb lattices [47,48]. Based on our results for graphene on TMDCs, where sizable PIA SOC has been found, we propose that it could also be realized by means of van der Waals heterostructures with flat graphene.…”

“…We propose to use a QAHE phase with C = 1 induced by a nontrivial gap at an M point [47,48] and add proximity s-wave superconductivity to it. We consider the real-space Hamiltonian from Eq.…”

Intrinsic Quantum Anomalous Hall Effect with In-Plane Magnetization: Searching Rule and Material Prediction

“…3(b), (d) and (f), respectively. If the mirror plane is perpendicular to the in-plane magnetization, the mirror symmetry will be conserved [18][19][20]. Otherwise, the mirror symmetry will be broken.…”

“…In 2013, based on 2D point group symmetry analysis, Liu et al has theoretically verified that the in-plane magnetization can also induce QAHE, once it breaks all the mirror symmetries [18]. Later on, Qiao et al propose two other buckled hexagonal lattices [19,20] to achieve the same goal. However, most proposals are toy model calculations, and the underlying relationship between magnetic anisotropy and local electronic structure has not been established.…”

Large-Gap Quantum Anomalous Hall Effect in Monolayer Halide Perovskite

“…Ever since the experimental discovery of graphene and topological insulators, various recipes were proposed to produce the quantum Hall effect without external magnetic field, i.e., quantum anomalous Hall effect (QAHE). Two representative categories are monolayer atomic crystals (e.g., graphene and graphene-like materials) [2][3][4] and magnetic topological insulators [5][6][7][8]. On one side, in 2010 it was theoretically reported that graphene can open up a band gap to harbor QAHE in the presence of both Rashba spin-orbit coupling and exchange field [3].…”