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arXiv · 1907.00261

Intrinsic quantized anomalous Hall effect in a moiré heterostructure

M. Serlin·C. L. Tschirhart·H. Polshyn·Y. Zhang·J. Zhu·K. Watanabe·T. Taniguchi·L. Balents·A. F. Young
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Abstract

We report the observation of a quantum anomalous Hall effect in twisted bilayer graphene showing Hall resistance quantized to within .1\% of the von Klitzing constant $h/e^2$ at zero magnetic field.The effect is driven by intrinsic strong correlations, which polarize the electron system into a single spin and valley resolved moiré miniband with Chern number $C=1$. In contrast to extrinsic, magnetically doped systems, the measured transport energy gap $Δ/k_B\approx 27$~K is larger than the Curie temperature for magnetic ordering $T_C\approx 9$~K, and Hall quantization persists to temperatures of several Kelvin. Remarkably, we find that electrical currents as small as 1~nA can be used to controllably switch the magnetic order between states of opposite polarization, forming an electrically rewritable magnetic memory.

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M. Serlin, C. L. Tschirhart, H. Polshyn, Y. Zhang, J. Zhu, K. Watanabe, T. Taniguchi, L. Balents, A. F. Young. 2019-06-29. Intrinsic quantized anomalous Hall effect in a moiré heterostructure. https://doi.org/10.1126/science.aay5533

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