High-Chern-number and high-temperature quantum Hall effect without Landau levels

Jun Ge; Yanzhao Liu; Jiaheng Li; Hao Li; Tianchuang Luo; Yang Wu; Yong Xu; Jian Wang

doi:10.1093/nsr/nwaa089

High-Chern-number and high-temperature quantum Hall effect without Landau levels

Natl Sci Rev. 2020 Aug;7(8):1280-1287. doi: 10.1093/nsr/nwaa089. Epub 2020 Apr 30.

Authors

Jun Ge¹, Yanzhao Liu¹, Jiaheng Li², Hao Li³, Tianchuang Luo¹, Yang Wu⁴, Yong Xu², Jian Wang¹

Affiliations

¹ International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China.
² State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China.
³ School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China.
⁴ Tsinghua-Foxconn Nanotechnology Research Center and Department of Physics, Tsinghua University, Beijing 100084, China.

Abstract

The quantum Hall effect (QHE) with quantized Hall resistance of h/νe ² started the research on topological quantum states and laid the foundation of topology in physics. Since then, Haldane proposed the QHE without Landau levels, showing nonzero Chern number |C| = 1, which has been experimentally observed at relatively low temperatures. For emerging physics and low-power-consumption electronics, the key issues are how to increase the working temperature and realize high Chern numbers (C > 1). Here, we report the experimental discovery of high-Chern-number QHE (C = 2) without Landau levels and C = 1 Chern insulator state displaying a nearly quantized Hall resistance plateau above the Néel temperature in MnBi₂Te₄ devices. Our observations provide a new perspective on topological matter and open new avenues for exploration of exotic topological quantum states and topological phase transitions at higher temperatures.

Keywords: Chern insulator; high Chern number; high temperature; quantum Hall effect without Landau levels; topological matter; topological quantum states.