title: Topological magnetic insulators with corundum structure.
abstract: Topological insulators are new states of quantum matter in which surface states residing in the bulk insulating gap are protected by time-reversal symmetry. When a proper kind of antiferromagnetic long-range order is established in a topological insulator, the system supports axionic excitations. In this Letter, we study theoretically the electronic states in a transition metal oxide of corundum structure, in which both spin-orbit interaction and electron-electron interaction play crucial roles. A tight-binding model analysis predicts that materials with this structure can be strong topological insulators. Because of the electron correlation, an antiferromagnetic order may develop, giving rise to a topological magnetic insulator phase with axionic excitations.
authors.affiliation: Department of Physics, Tsinghua University, Beijing 100084, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.forename: Rundong
authors.initials: R
authors.lastname: Li
authors.forename: Shou-Cheng
authors.initials: SC
authors.lastname: Zhang
authors.forename: Xiao-Liang
authors.initials: XL
authors.lastname: Qi