First-principles study on correlations and contact barriers in magnetic Fe₃GeTe₂/CrGeTe₃ heterobilayer

Recently the novel magnetic properties of van der Waals ferromagnetic layered metallic Fe₃GeTe₂ and semiconducting CrGeTe₃ materials have drawn attention in their mono- or few-layers compounds. Based on a first-principles computational method treating the local Coulomb repulsion of U and Hund’s coupling of J separately, we present the effects of these important interactions on the electronic and magnetic structures of a layered ferromagnetic semiconductor CrGeTe₃. With the proper U and J values for CrGeTe₃, we also show the structural, electronic, and magnetic structures of a layered magnetic van der Waals Fe₃GeTe₂/CrGeTe₃ heterobilayer. We discuss the possible stacking structures and the band alignment including the contact barrier height with and without the electrostatic gating in the heterobilayer.