Large Anomalous Hall Effect in Topological Insulators with Proximitized Ferromagnetic Insulators

Masataka Mogi; Taro Nakajima; Victor Ukleev; Atsushi Tsukazaki; Ryutaro Yoshimi; Minoru Kawamura; Kei S Takahashi; Takayasu Hanashima; Kazuhisa Kakurai; Taka-Hisa Arima; Masashi Kawasaki; Yoshinori Tokura

doi:10.1103/PhysRevLett.123.016804

Large Anomalous Hall Effect in Topological Insulators with Proximitized Ferromagnetic Insulators

Phys Rev Lett. 2019 Jul 3;123(1):016804. doi: 10.1103/PhysRevLett.123.016804.

Authors

Masataka Mogi¹, Taro Nakajima², Victor Ukleev^{2

3}, Atsushi Tsukazaki⁴, Ryutaro Yoshimi², Minoru Kawamura², Kei S Takahashi^{2

5}, Takayasu Hanashima⁵, Kazuhisa Kakurai^{2

6}, Taka-Hisa Arima^{2

7}, Masashi Kawasaki^{1

2}, Yoshinori Tokura^{2

8}

Affiliations

¹ Department of Applied Physics and Quantum Phase Electronics Center (QPEC), University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan.
² RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan.
³ Laboratory for Neutron Scattering and Imaging (LNS), Paul Scherrer Institute (PSI), CH-5232, Villigen, Switzerland.
⁴ Institute for Materials Research, Tohoku University, Sendai, Miyagi 980-8577, Japan.
⁵ PRESTO, Japan Science and Technology Agency (JST), Chiyoda-ku, Tokyo 102-0075, Japan.
⁶ Comprehensive Research Organization for Science and Society (CROSS), Tokai, Ibaraki 319-1106, Japan.
⁷ Department of Advanced Materials Science, University of Tokyo, Kashiwa, Chiba 277-8561, Japan.
⁸ Tokyo College, University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan.

PMID: 31386415
DOI: 10.1103/PhysRevLett.123.016804

Abstract

We report a proximity-driven large anomalous Hall effect in all-telluride heterostructures consisting of the ferromagnetic insulator Cr_{2}Ge_{2}Te_{6} and topological insulator (Bi,Sb)_{2}Te_{3}. Despite small magnetization in the (Bi,Sb)_{2}Te_{3} layer, the anomalous Hall conductivity reaches a large value of 0.2e^{2}/h in accord with a ferromagnetic response of the Cr_{2}Ge_{2}Te_{6}. The results show that the exchange coupling between the surface state of the topological insulator and the proximitized Cr_{2}Ge_{2}Te_{6} layer is effective and strong enough to open the sizable exchange gap in the surface state.