Chern junctions in Moiré-Patterned Graphene/PbI2

Abstract: Expanding the moir\'e material library continues to unlock novel quantum phases and emergent electronic behaviors. In this work, we introduce PbI2 into the moir\'e family and investigate the magnetotransport properties of moir\'e superlattice in a hexagonal boron nitride/graphene/PbI2 heterostructures. In high-field quantum Hall regime, we observe a robust dissipationless transport at charge neutrality point, indicative of incompressible states stabilized at the filling factor vh = 0. Additionally, a fractional conductance plateau at 2/3 e2/h emerges, which we attribute to a Chern junction between domains with distinct Chern numbers originating from moir\'e-modulated and conventional integer quantum Hall states. The moir\'e Hofstadter spectrum displays an unconventional flavor sequence, likely influenced by proximity-induced spin-orbit coupling from the PbI2 layer. We also see coherent electronic interference along lines with Chern number vm = -2. These findings position PbI2-based heterostructures as a versatile platform for realizing spin-orbit-enhanced moir\'e phenomena and engineering coherent edge transport in two-dimensional quantum materials.