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Large Anomalous Hall Effect in Topological Insulators with Proximitized Ferromagnetic Insulators
Masataka Mogi1, Taro Nakajima2, Victor Ukleev2,3
1Department of Applied Physics and Quantum Phase Electronics Center (QPEC), University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan.
Physical Review Letters
|August 7, 2019
Summary
We observed a significant anomalous Hall effect in telluride heterostructures. This effect arises from the strong magnetic coupling between a ferromagnetic insulator and a topological insulator.
Area of Science:
- Condensed matter physics
- Materials science
- Spintronics
Background:
- Topological insulators (TIs) possess unique surface states with potential applications in spintronics.
- Proximity effects in heterostructures can induce novel phenomena by coupling different material properties.
Purpose of the Study:
- To investigate the anomalous Hall effect in all-telluride heterostructures combining a ferromagnetic insulator and a topological insulator.
- To understand the role of exchange coupling in mediating the observed phenomena.
Main Methods:
- Fabrication of Cr_{2}Ge_{2}Te_{6}/(Bi,Sb)_{2}Te_{3} heterostructures.
- Measurement of the anomalous Hall effect and magnetization.
Main Results:
- A large anomalous Hall conductivity of 0.2e^{2}/h was observed, correlating with the ferromagnetic response of Cr_{2}Ge_{2}Te_{6}.
- Evidence of strong exchange coupling between the topological insulator surface states and the ferromagnetic insulator was found.
- A sizable exchange gap was opened in the topological insulator surface state.
Conclusions:
- Proximity coupling in Cr_{2}Ge_{2}Te_{6}/(Bi,Sb)_{2}Te_{3} heterostructures effectively induces a large anomalous Hall effect.
- The strong exchange interaction is key to manipulating the electronic properties of topological insulator surface states.
- These findings open avenues for novel spintronic devices utilizing magnetic proximity effects.
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