Γ-Valley Transition-Metal-Dichalcogenide Moirè Bands

The valence band maxima of most group-VI transition metal dichalcogenide thin films remain at the Γ-point all the way from bulk to bilayer. In this talk, I will describe a recently developed continuum theory of the moirè minibands that are formed in the valence bands of Γ-valley homobilayers by a small relative twist. Our effective theory is benchmarked against large-scale ab initio electronic structure calculations that account for lattice relaxation. As a consequence of an emergent D_6 symmetry we find that low-energy Γ-valley moirè holes differ qualitatively from their K-valley counterparts addressed previously; in energetic order the first three bands realize i) a single-orbital model on a honeycomb lattice, ii) a two-orbital model on a honeycomb lattice, and iii) a single-orbital model on a kagome lattice