Nature of the hysteretic halo boundaries

Determine whether the consecutive hysteretic transitions observed at the boundaries of the ν=−2 metallic halo represent separate symmetry-broken phases or arise from spatial inhomogeneity.

Background

The metallic halo surrounding the correlated insulator at ν=−2 exhibits hysteresis under density or displacement-field sweeps, suggesting first-order transitions. In some regions, two hysteretic transitions occur consecutively. The available measurements do not establish whether these transitions correspond to distinct broken-symmetry phases or instead reflect spatial variation within the device.

References

In some regions we see consecutive hysteretic transitions, although we cannot tell whether these represent separate symmetry-broken phases or result from spatial inhomogeneity.

— Incipient superconductivity and tunable Chern insulators in twisted Bernal bilayer-trilayer graphene  (2609.30202 - Waleffe et al., 24 Sep 2026) in Section “Maximal T_c near the insulating boundary”