GdN thin film: Chern insulating state on square lattice

• Main Authors: Li, Zhi, Kim, Jinwoong, Kioussis, Nicholas, Ning, Shu-Yu, Su, Haibin, Iitaka, Toshiaki, Tohyama, Takami, Yang, Xinyu, Zhang, Jiu-Xing
• Other Authors: School of Materials Science & Engineering
• Format: Article
• Language: English
• Published: 2016
• Subjects: Materials Science and Engineering
• Online Access: https://hdl.handle.net/10356/81734; http://hdl.handle.net/10220/39647
• Institution: Nanyang Technological University

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.