Topological phases in intercalated epitaxial graphene

Intercalation is one of the effective methods to functionally manipulate the electronic structure of epitaxial graphene. Here, using first-principles density functional theory calculations, we design 2D topological insulators in epitaxial graphene via intercalation. We find that the electronic band structure near the Fermi energy shows Dirac-cone type or quadratic band dispersion depending on the type of intercalants, and topologically nontrivial band gap opens due to the considerable strength of the spin-orbit coupling. Our results indicate that the intercalation is a promising way to realize topological phases in graphene, and could be important in future nano device applications of graphene.