Observation of one-dimensional ballistic valley transport in the curved boundary of bilayer graphene

Bilayer graphene is a two-layered hexagonal crystal of carbon atoms that shows novel and interesting valley-based phenomena. The manipulation of the valley degree of freedom in graphene have been proposed by different methods such as by exploiting topological confined zero-mode states at domain walls or by creating graphene nanoribbons with zig-zag boundaries. Future dissipationless valleytronic devices require absence of short range disorder, in order to achieve a ballistic valley transport, and it is desirable that they have a channel with atomic width dimensions. In this work we show strong evidences that a ballistic valley conduction may be achieved in a one-dimensional channel formed along the curved boundary of a folded bilayer graphene. In our high quality devices of graphene encapsulated in between h-BN crystals, we measured a ballistic conductance near of G=4e²/h with zero-magnetic fields. We envision that such new ultra-thin valleytronic platform could either be exploit as a novel dissipationless electronic quantum device as well could let to the discovery of novel exciting properties of matter, such as graphene-based superconducting effects.