Magnetizing topological surface states of Bi<sub>2</sub>Se<sub>3</sub> with a CrI<sub>3</sub> monolayer.

Hou, Yusheng; Kim, Jeongwoo; Wu, Ruqian · Sci Adv · 2019

basic_science · Level V

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Abstract

To magnetize surfaces of topological insulators without damaging their topological feature is a crucial step for the realization of the quantum anomalous Hall effect (QAHE) and remains as a challenging task. Through density functional calculations, we found that adsorption of a semiconducting two-dimensional van der Waals (2D-vdW) ferromagnetic CrI<sub>3</sub> monolayer can create a sizable spin splitting at the Dirac point of the topological surface states of Bi<sub>2</sub>Se<sub>3</sub> films. Furthermore, general rules that connect different quantum and topological parameters are established through model analyses. This work provides a useful guideline for the realization of QAHE at high temperatures in heterostructures of 2D-vdW magnetic monolayers and topological insulators.