Theoretical design of highly correlated electron states in delafossite heterostructures

Abstract: Delafossites represent natural heterostructures which can host rather different electronic characteristics in their constituting layers. The design of novel heterostructure architectures highlighting the competition between such varying layer properties is promising from the viewpoint of basic research as well as for future technological applications. By means of the combination of density functional theory and dynamical mean-field theory, we here unveil the formation of highly correlated electron states in delafossite heterostructures build from metallic PdCrO$_2$ and insulating AgCrO$_2$. Due to the sophisticated coupling between layers of strong and of weak internal electron-electron interaction, correlation-induced semimetals at ambient temperature and doped Mott-insulators at lower temperature are predicted. The unique electronic structure of delafossite heterostructures opens a door to research on novel challenging quantum matter.