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Exchange-Biased Quantum Anomalous Hall Effect



Peng Zhang, Purnima P. Balakrishnan, Christopher Eckberg, Peng Deng, Tomohiro Nozaki, Sukong Chong, Patrick Quarterman, Megan Holtz, Brian B. Maranville, Gang Qiu, Lei Pan, Eve Emmanouilidou, Ni Ni, Masashi Sahashi, Alexander Grutter, Kang L. Wang


The quantum anomalous Hall (QAH) effect is characterized by a dissipationless chiral edge state with a quantized Hall resistance at zero magnetic field. Manipulating the QAH state is of great importance in both the understanding of topological quantum physics and the implementation of dissipationless electronics. Here, the QAH effect is realized in the magnetic topological insulator Cr-doped (Bi,Sb)2Te3 (CBST) grown on an uncompensated antiferromagnetic insulator Al-doped Cr2O3. Through polarized neutron reflectometry (PNR), a strong exchange coupling is found between CBST and Al-Cr2O3 surface spins fixing interfacial magnetic moments perpendicular to the film plane. The interfacial coupling results in an exchange-biased QAH effect. This study further demonstrates that the magnitude and sign of the exchange bias can be effectively controlled using a field training process to set the magnetization of the Al-Cr2O3 layer. It demonstrates the use of the exchange bias effect to effectively manipulate the QAH state, opening new possibilities in QAH-based spintronics.
Advanced Materials


quantum anomalous Hall effect, magnetic topological insulator, polarized neutron reflectometry, ferrimagnet, exchange coupling, spintronics


Zhang, P. , Balakrishnan, P. , Eckberg, C. , Deng, P. , Nozaki, T. , Chong, S. , Quarterman, P. , Holtz, M. , Maranville, B. , Qiu, G. , Pan, L. , Emmanouilidou, E. , Ni, N. , Sahashi, M. , Grutter, A. and Wang, K. (2023), Exchange-Biased Quantum Anomalous Hall Effect, Advanced Materials, [online],, (Accessed May 23, 2024)


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Created May 19, 2023, Updated March 11, 2024