GdN thin film: Chern insulating state on square lattice

作者:Li, Zhi*; Kim, Jinwoong; Kioussis, Nicholas; Ning, Shu-Yu; Su, Haibin; Iitaka, Toshiaki; Tohyama, Takami; Yang, Xinyu; Zhang, Jiu-Xing
来源:Physical Review B, 2015, 92(20): 201303.
DOI:10.1103/PhysRevB.92.201303

摘要

Using first-principles calculations, we predict a Chern insulating phase in thin films of the ferromagnetic semimetal GdN. In contrast to previously proposed Chern insulator candidates, which mostly rely on honeycomb lattices, this system affords a great chance to realize the quantum anomalous Hall effect on a square lattice without either a magnetic substrate or transition metal doping, making synthesis easier. The band inversion between the 5d orbitals of Gd and 2p orbitals of N is verified by first-principles calculations based on density functional theory, and the band gap can be as large as 100 meV within the GdN trilayer. With a further increase of film thickness, the band gap tends to close and the metallic bulk property becomes obvious.