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Title: Nature of the extended quantum anomalous Hall state
Plain: At the lowest temperatures pentalayer graphene shows an integer quantized Hall resistance over a wide range of electron densities, replacing the fractional states, and the electronic structure behind it is unknown.
Precise: Lu et al. (Nature 637, 1090, 2025; arXiv:2408.10203) reported an extended integer quantum anomalous Hall state, $R_{xy} = h/e^{2}$ with vanishing $R_{xx}$ over a continuous range of moire filling from $\nu \sim 0.5$ to $\sim 1.3$, appearing at the lowest temperatures in rhombohedral pentalayer graphene/hBN. Identify the state: an anomalous Hall crystal (electron crystal with Chern number 1) pinned by disorder, a moire-commensurate state, or another order. An answer determines whether translation symmetry is broken and how the crystal period varies with density.
Settled by: Local imaging (STM or scanning single-electron transistor) of a density-dependent crystal period coexisting with quantized Hall response.
Kind: well-posed
Answer type: identification
References: (empty)
Literature status: contested
Status note: Interpretation as an anomalous Hall crystal is not confirmed by imaging as of 2026.
Posed since: 2024