Orbitally selective Mott phase in electron-doped twisted transition metal-dichalcogenides: A possible realization of the Kondo lattice model

Abstract

Moiré superpotentials in two-dimensional materials allow unprecedented control of the ratio between kinetic and interaction energy. By this they pave the way to study a wide variety of strongly correlated physics under a new light. In particular, the transition-metal dichalcogenides (TMDs) are promising candidate "quantum simulators"of the Hubbard model on a triangular lattice. Indeed, Mott and generalized Wigner crystals have been observed in such devices. Here we theoretically propose to extend this model into the multiorbital regime by focusing on electron-doped systems at filling higher than 2. As opposed to hole bands, the electronic bands in TMD materials include two, nearly degenerate species, which can be viewed as two orbitals with different effective mass and binding energy. Using realistic band-structure parameters and a slave-rotor mean-field theory, we find that an orbitally selective Mott (OSM) phase can be stabilized over a wide range of fillings, where one band is locked in a commensurate Mott state, while the other remains itinerant with variable density. This scenario thus realizes the basic ingredients in the Kondo lattice model: a periodic lattice of localized magnetic moments interacting with metallic states. We also discuss possible experimental signatures of the OSM state.