Realizing axion insulator state with a uniform magnetization considerably facilitates experimental explorations of the intriguing topological magnetoelectric effect, a hallmark of three-dimensional (3D) topological insulators (TIs). Through density functional theory calculations and four-band model studies, we find that magnetic ions Cr3+ in monolayer CrI3 and Mn2+ in septuple-layer MnBi2Se4 have opposite exchange couplings to the topological surface states of 3D TI Bi2Se3. As an exciting result of such opposite exchange couplings, axion insulator state is realized by a uniform magnetization in CrI3/Bi2Se3/MnBi2Se4 heterostructure. Our work opens up opportunities for exploring topological magnetoelectric effect realized by the uniform magnetization induced axion insulator state in heterostructures of 3D TIs and two-dimensional van der Waals ferromagnetic insulators.
@article{arxiv.1902.03372,
title = {Axion Insulator State with ferromagnetic ordering in CrI3/Bi2Se3/MnBi2Se4 Heterostructure},
author = {Y. S. Hou and R. Q. Wu},
journal= {arXiv preprint arXiv:1902.03372},
year = {2020}
}