Zero-line modes at stacking faulted domain walls in multilayer graphene

摘要

Rhombohedral multilayer graphene is a physical realization of the chiraltwo-dimensional electron gas that can host zero-line modes (ZLMs), also knownas kink states, when the local ap opened by inversion symmetry breakingpotential changes sign in real space. Here we study how the variations in thelocal stacking coordination of multilayer graphene affects the formation of theZLMs. Our analysis indicates that the valley Hall effect develops whenever aninterlayer potential difference is able to open up a band gap in stackingfaulted multilayer graphene, and that ZLMs can appear at the domain wallsseparating two distinct regions with imperfect rhombohedral stackingconfigurations. Based on a tight-binding formulation with distant hopping termsbetween carbon atoms, we first show that topologically distinct domainscharacterized by the valley Chern number are separated by a metallic regionconnecting AA and AA$'$ stacking line in the layer translation vector space. Wefind that gapless states appear at the interface between the two stackingfaulted domains with different layer translation or with opposite perpendicularelectric field if their valley Chern numbers are different.