Quantum Hall states stabilized in semi-magnetic bilayers of topological insulators.
By breaking the time-reversal symmetry in three-dimensional topological insulators with the introduction of spontaneous magnetization or application of magnetic field, the surface states become gapped, leading to quantum anomalous Hall effect or quantum Hall effect, when the chemical potential locates inside the gap. Further breaking of inversion symmetry is possible by employing magnetic topological insulator heterostructures that host non-degenerate top and bottom surface states. Here we demonstrate the tailored-material approach for the realization of robust quantum Hall states in the bilayer system, in which the cooperative or cancelling combination of the anomalous and ordinary Hall responses from the respective magnetic and non-magnetic layers is exemplified. The appearance of quantum Hall states at filling factor 0 and +1 can be understood by the relationship of energy band diagrams for the two independent surface states. The designable heterostructures of magnetic topological insulator may explore a new arena for intriguing topological transport and functionality.
Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), University of Tokyo, 7-3-1Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
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Yoshimi
Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), University of Tokyo, 7-3-1Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
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Yasuda
Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan.|PRESTO, Japan Science and Technology Agency (JST), Chiyoda-ku, Tokyo 102-0075, Japan.
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Tsukazaki
RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan.
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Takahashi
Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), University of Tokyo, 7-3-1Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.|RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan.
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Nagaosa
Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), University of Tokyo, 7-3-1Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.|RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan.
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Kawasaki
Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), University of Tokyo, 7-3-1Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.|RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan.
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Tokura