"Emerging weak localization effects on a topological insulator–insulating ferromagnet (Bi2Se3-EuS) interface"

Qi I. Yang: Merav Dolev, Li Zhang, Jinfeng Zhao, Alexander D. Fried, Elizabeth Schemm, Min Liu, Alexander Palevski, Ann F. Marshall, Subhash H. Risbud, and Aharon Kapitulnik; Physical Review B, 08/28/13.

Additional Authors: Merav Dolev, Li Zhang, Jinfeng Zhao, Alexander D. Fried, Elizabeth Schemm, Min Liu, Alexander Palevski, Ann F. Marshall, Subhash H. Risbud, and Aharon Kapitulnik

Abstract:

Thin films of topological insulator Bi2Se3 were deposited directly on insulating ferromagnetic EuS. Unusual negative magnetoresistance was observed near the zero field below the Curie temperature TC, resembling the weak localization effect; whereas the usual positive magnetoresistance was recovered above TC. Such negative magnetoresistance was only observed for Bi2Se3 layers thinner than t∼4 nm, when its top and bottom surfaces are coupled. These results provide evidence for a proximity effect between a topological insulator and an insulating ferromagnet, laying the foundation for future realization of the half-integer quantized anomalous Hall effect in three-dimensional topological insulators.