image: Coexistence of chiral DW and QAHE can be achieved in QAH insulators with sizable Dzyaloshinskii–Moriya interactions. Domain walls act as natural boundaries separating edge states with opposite chirality. Controlling magnetic domain walls by various approaches such as external magnetic fields, excitations, and spin currents can lead to the reconstruction of the QAHE. view more
Credit: Beijing Zhongke Journal Publising Co. Ltd.
Research Background
Magnetic chiral DWs are a class of topological structures with discrete symmetries. As the boundary between domains with opposite magnetization, this structure is widely used in spintronic memory and logic devices. The emergence of chiral DWs requires a material system possesses strong Dzyaloshinskii–Moriya interactions. The quantum anomalous Hall effect is another electronic topological phase, which exhibits chiral edge states without energy dissipation, and has broad application prospects in ultra-low power electronic devices. However, achieving the coexistence of two topological states in realistic materials and further realize the chiral DW-controlled QAH edge states are still important challenges.
Content
Recently, by using first-principles calculations, Wannier tight-binding model and micromagnetic simulations, Professor Hongxin Yang and Dr. Qirui Cui from Nanjing University demonstrate that the two-dimensional magnets could combine non-trivial electronic states and large Dzyaloshinskii–Moriya interactions. They show that the topological magnetic structure and high-temperature quantum anomalous Hall effect can coexist in VSe2 and Fe2XI (X=Cl, Br) monolayers. Moreover, they find that the reconfigurable quantum anomalous Hall effect can be realized under the cooperation of an external magnetic and temperature field. The fast motion of the DW driven by the spin-orbit torque finally leads to the precise and fast manipulation of the dissipationless chiral edge state.
Discussion and perspective
Based on the inversion symmetry-broken two-dimensional magnet, non-trivial electronic states and strong Dzyaloshinskii–Moriya interactions are obtained simultaneously, and the coexistence of chiral DWs and QAHE is further realized. More interestingly, the effective control of quantized edge state is achieved in such systems by applying the magnetic field, thermal excitation, and spin-orbit torque to modify the morphology and position of chiral DWs. This work thus provides a novel feasible route for tuning the quantum spin transport.
See the article:
Quantum Anomalous Hall Effects Controlled by Chiral Domain Walls
https://iopscience.iop.org/article/10.1088/0256-307X/40/3/037502
Journal
Chinese Physics Letters
Article Title
Quantum Anomalous Hall Effects Controlled by Chiral Domain Walls
Article Publication Date
12-Feb-2023