Locally resolved electronic textures of reconstruction domains in marginally twisted monolayer-bilayer graphene

Controlling the stacking and rotational registry of graphene layers provides a powerful handle on atomic-scale structural reconstructions that alter the electronic landscape at the nanoscale. In particular, this governs how massless and massive Dirac fermions coexist and interact at the monolayer-bilayer graphene interface. In the limit of marginal twist, the system reconstructs into domains of distinct vertical stacking order, introducing characteristic electronic properties and new electronic length scales, a regime that, despite its structural richness, remains largely unexplored. Here, using scanning tunnelling microscopy and spectroscopy, we demonstrate that at very low rotation angles the monolayer-bilayer graphene system relaxes into a network of three distinct stacking domains with individual electronic textures revealed through spatially resolved spectroscopic mapping and corroborated by computed local density of states. We report switching of the hierarchy of the tunnelling characteristics between Bernal and rhombohedral domains as a function of bias voltage. Furthermore, the measured spectroscopic maps exhibit theoretically anticipated domain wall 'twirling' around energetically unfavorable AAB stacking nodes, promoted by out-of-plane deformations. Our results shed light on fundamental structure-property relationships underpinning moir\'e-driven phenomena, opening new avenues for harnessing structural degrees of freedom in van der Waals heterostructures.