Majorana zero modes in encapsulated bilayer graphene

The search of solid state platforms exhibiting robust topological superconductivity and Majorana bound states is beginning to expand from semiconducting nanowires and related systems to two-dimensional crystals. Some previous proposals to generate Majoranas in graphene relied on interactions in the Quantum Hall regime. In this work we study the feasibility of an alternative approach that exploits graphene bilayers encapsulated in transition metal dichalcogenides, and requires potentially much smaller magnetic fields. The strong spin-orbit coupling induced on the graphene bilayer is known to open a gap in the bilayer with fragile helical edge states. We show that, when subject to an in-plane Zeeman field, armchair edge states can be proximitized into a p-wave one-dimensional topological superconductor by contacting them with a conventional superconductor. We demonstrate the emergence of Majorana bound states, both with crystallographically perfect side-contacted edges and also in more realistic vertically-contacted samples. The computed phase diagram generalizes that of the Oreg-Lutchyn model for Rashba nanowires, and suggests the existence of a topological phase within experimental reach.