Topological-magnetic proximity effect in Sb2Te3/CrI3 heterostructures

The topological-magnetic proximity effect between Sb2Te3 and a CrI3 monolayer is studied using a first-principles method. According to the results, a compressive strain of the CrI3 monolayer leads to a global energy gap at the topological surface states of Sb2Te3. The gap size is sensitive to the separation distance between Sb2Te3 and CrI3, and the gap opening mechanism is attributed to the exchange field from CrI3. This study is of significance to design systems of topological magnetoelectric effect as well as the understanding and control of the electronic behaviors in Sb2Te3/CrI3 and other topological insulator/magnetic insulator heterostructures alike.