Extended Data Fig. 5: Schematic plot illustrating the ETO edge state on one side of a Hall bar.
From: Excitonic topological order in imbalanced electron–hole bilayers
Left and Middle, B⊥ = 0: The bulk of the imbalanced e–h bilayer opens a many-body gap, with its edge state formed by a pair of the weakly-bound particle (−e) and hole (+e) channels, as demonstrated by the theory of ETO; the robustness of the edge states is protected by a BCS-like bulk gap. Considering the quasiparticle-quasihole symmetry near the Fermi level, the excitonic edge state is viewed as equivalent to a helical-like state containing two oppositely propagating (−e) channels (Sec. V of Supplementary Information). Right, when B⊥ is applied, the two channels are spatially separated due to the Lorentz force, forming inner and outer loops in a Hall bar. The dotted lines denote the scattering between the two channels, which decays with increasing B⊥ but always exists in realistic samples, explaining why the Hall resistance does not exactly quantize in chiral-like transport.
