Quantized resistance revealed at the criticality of the quantum anomalous Hall phase transitions

Peng Deng; Peng Zhang; Christopher Eckberg; Su Kong Chong; Gen Yin; Eve Emmanouilidou; Xiaoyu Che; Ni Ni; Kang L Wang

doi:10.1038/s41467-023-40784-y

Quantized resistance revealed at the criticality of the quantum anomalous Hall phase transitions

Nat Commun. 2023 Sep 9;14(1):5558. doi: 10.1038/s41467-023-40784-y.

Authors

Peng Deng¹, Peng Zhang², Christopher Eckberg^{3

4

5}, Su Kong Chong², Gen Yin², Eve Emmanouilidou⁶, Xiaoyu Che², Ni Ni⁶, Kang L Wang^{7

8}

Affiliations

¹ Department of Electrical and Computer Engineering, University of California Los Angeles, Los Angeles, California, 90095, USA. dengpeng@g.ucla.edu.
² Department of Electrical and Computer Engineering, University of California Los Angeles, Los Angeles, California, 90095, USA.
³ Fibertek Inc, Herndon, VA, 20783, USA.
⁴ US Army Research Laboratory, Adelphi, MD, 20783, USA.
⁵ US Army Research Laboratory, Playa Vista, CA, 20783, USA.
⁶ Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA, 90095, USA.
⁷ Department of Electrical and Computer Engineering, University of California Los Angeles, Los Angeles, California, 90095, USA. wang@ee.ucla.edu.
⁸ Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA, 90095, USA. wang@ee.ucla.edu.

Abstract

In multilayered magnetic topological insulator structures, magnetization reversal processes can drive topological phase transitions between quantum anomalous Hall, axion insulator, and normal insulator states. Here we report an examination of the critical behavior of two such transitions: the quantum anomalous Hall to normal insulator (QAH-NI), and quantum anomalous Hall to axion insulator (QAH-AXI) transitions. By introducing a new analysis protocol wherein temperature dependent variations in the magnetic coercivity are accounted for, the critical behavior of the QAH-NI and QAH-AXI transitions are evaluated over a wide range of temperature and magnetic field. Despite the uniqueness of these different transitions, quantized longitudinal resistance and Hall conductance are observed at criticality in both cases. Furthermore, critical exponents were extracted for QAH-AXI transitions occurring at magnetization reversals of two different magnetic layers. The observation of consistent critical exponents and resistances in each case, independent of the magnetic layer details, demonstrates critical behaviors in quantum anomalous Hall transitions to be of electronic rather than magnetic origin. Our finding offers a new avenue for studies of phase transition and criticality in QAH insulators.

Abstract

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