Graphene Nanoribbon -- Transition Metal Dichalcogenide Heterostructures

In this work, we study the electronic structure of heterostructures formed by graphene nanoribbons (GNRs) and monolayers of transition metal dichalcogenides (TMDs), such as MoS₂. We study various stacking configurations between GNRs and TMDs and show the possibility to engineer the band-gap of the ribbon and remove its spin degeneracy. In particular, we find that in heterostructures in which the TMD is a semiconductor the strong spin-orbit coupling of the TMD can induce, via proximity effect, a significant enhancement of the spin-orbit coupling in the GNR's conduction and valence bands. We also study the case in which the TMD is NbSe₂. This is an interesting case because NbSe₂ is metallic at room temperature and superconducting at low temperatures. The strong enhancement of the spin-orbit coupling in the ribbon and the fact that one of the TMD monolayers, NbSe₂, is superconducting at low temperatures make GNR TMD heterostructures a promising platform for the realization of quasi one-dimensional superconducting topological states supporting Majorana zero modes.