Electrical Manipulation of Topological Phases in a Quantum Anomalous Hall Insulator

Journal Article · Wed Feb 08 00:00:00 EST 2023 · Advanced Materials

DOI:https://doi.org/10.1002/adma.202207622· OSTI ID:1961880

Chong, Su Kong  ^[1]; Zhang, Peng ^[1]; Li, Jie ^[2]; Zhou, Yinong ^[2]; Wang, Jingyuan ^[2]; Zhang, Huairuo ^[3]; Davydov, Albert V. ^[4]; Eckberg, Christopher ^[5]; Deng, Peng ^[1]; Tai, Lixuan ^[1]; Xia, Jing ^[2]; Wu, Ruqian ^[2]; Wang, Kang L.  ^[1]

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1. Department of Electrical and Computer Engineering University of California, Los Angeles Los Angeles CA 90095 USA
2. Department of Physics and Astronomy University of California, Irvine Irvine CA 92697 USA
3. Theiss Research Inc. La Jolla CA 92037 USA, Materials Science and Engineering Division National Institute of Standards and Technology (NIST) Gaithersburg MD 20899 USA
4. Theiss Research Inc. La Jolla CA 92037 USA
5. Department of Electrical and Computer Engineering University of California, Los Angeles Los Angeles CA 90095 USA, Fibertek Inc. Herndon VA 20171 USA, US Army Research Laboratory Adelphi MD 20783 USA, US Army Research Laboratory Playa Vista CA 90094 USA

Abstract Quantum anomalous Hall phases arising from the inverted band topology in magnetically doped topological insulators have emerged as an important subject of research for quantization at zero magnetic fields. Though necessary for practical implementation, sophisticated electrical control of molecular beam epitaxy (MBE)‐grown quantum anomalous Hall matter have been stymied by growth and fabrication challenges. Here, a novel procedure is demonstrated, employing a combination of thin‐film deposition and 2D material stacking techniques, to create dual‐gated devices of the MBE‐grown quantum anomalous Hall insulator, Cr‐doped (Bi,Sb) ₂ Te ₃ . In these devices, orthogonal control over the field‐induced charge density and the electric displacement field is demonstrated. A thorough examination of material responses to tuning along each control axis is presented, realizing magnetic property control along the former and a novel capability to manipulate the surface exchange gap along the latter. Through electrically addressing the exchange gap, the capabilities to either strengthen the quantum anomalous Hall state or suppress it entirely and drive a topological phase transition to a trivial state are demonstrated. The experimental result is explained using first principle theoretical calculations, and establishes a practical route for in situ control of quantum anomalous Hall states and topology.

• Sponsoring Organization: USDOE
• OSTI ID: 1961880
• Journal Information: Advanced Materials, Journal Name: Advanced Materials Vol. 35 Journal Issue: 11; ISSN 0935-9648
• Publisher: Wiley Blackwell (John Wiley & Sons)
• Country of Publication: Germany
• Language: English