Anomalous Z2 antiferromagnetic topological phase in pressurized SmB6

Abstract

Antiferromagnetic materials, whose time-reversal symmetry is broken, can be classified into the Z2 topology if they respect some specific symmetry. Since the theoretical proposal, however, no materials have been found to host the antiferromagnetic topological (AFT) phase to date. Here, for the first time, we demonstrate that the topological Kondo insulator SmB6 can be an AFT system when pressurized to undergo an antiferromagnetic phase transition. In addition to propose the possible candidate for an AFT material, in this work we also illustrate the anomalous topological surface states of the AFT phase which has not been discussed before. Originating from the interplay between the topological properties and the antiferromagnetic surface magnetization, the topological surface states of the AFT phase behave differently as compared with those of a topological insulator. Besides, the AFT insulators are also found promising in the generation of tunable spin currents, which is an important application in spintronics.