Energy spectrum of graphene and multi-layer graphene quantum dots with parabolic confinement.

Graphene is an ambipolar two-dimensional crystal consisting of a hexagonal lattice of carbon atoms. Quantum dots in graphene and multi-layer graphene can be created by parabolic confinement of hole/electron-doped regions in an electron/hole-doped graphene sample. We calculate the eigenenergy spectrum and the local density of states of graphene and multilayer quantum dots with parabolic confinement. Our results have implications for the scanning tunneling microscope (STM) experiments on graphene and multi-layer graphene quantum dots.