The interfacial effect on the anomalous Hall effect of magnetic topological insulators

A quantum anomalous Hall effect (QAHE) has been actively researched with great attention by virtue of its fascinating emergent phenomena of quantized Hall resistance. After theoretical works proposed that the QAHE can be realized when the time-reversal symmetry is broken in topological insulators by introducing ferromagnetic orders, the QAHE of magnetic topological insulators has been experimentally confirmed by various research groups. In this presentation, we investigate the interfacial effect, interplay between magnetic topological insulators (MTIs) and capping/buffer layers. First, we applied various materials as capping layers to investigate the capping layer dependence on Hall resistance of MTIs and significant enhancement of the Hall properties has been observed in Cr capped MTIs. Second, to understand the enhanced anomalous Hall effect on Cr capped MTIs, we performed several control tests. All results point out the proximity effect between Cr capping layer and MTIs as a dominant origin of the observed enhancement. This finding of interplay exchange coupling between Cr capping layers and the MTI will serve as the new platform to explore the high-temperature quantum anomalous Hall effect on MTI.