High-Chern-Number and High-Temperature Quantum Hall Effect without Landau Levels

TL;DR

This paper reports the experimental discovery of high-Chern-number (C=2) quantum Hall effect and C=1 Chern insulator state in MnBi2Te4 devices, achieving nearly quantized Hall resistance above the Ne9el temperature, advancing topological quantum states at higher temperatures.

Contribution

It demonstrates the realization of high-Chern-number and high-temperature quantum Hall effects without Landau levels, a significant advancement in topological physics.

Findings

Observation of C=2 quantum Hall effect in MnBi2Te4.

Nearly quantized Hall resistance plateau above Ne9el temperature.

Experimental evidence of topological phase transitions at higher temperatures.

Abstract

The quantum Hall effect (QHE) with quantized Hall resistance of h/{\nu}e2 starts the research on topological quantum states and lays the foundation of topology in physics. Afterwards, 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 nearly quantized Hall resistance plateau above the N\'eel 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.