Oral: Quadrupolar excitons and hybridized interlayer Mott insulator in a trilayer moiré superlattice

Transition metal dichalcogenide moiré heterojunctions in the type II alignment host not only interlayer excitons with permanent dipole moments but also exhibit novel correlated physics, owing to the presence of moiré flatbands. In this work, we present a new excitonic state, interlayer quadrupolar exciton in an angle-aligned symmetric WSe₂/WS₂/WSe₂ trilayer heterojunction. The quadrupolar exciton stems from the valence band hybridization. The interlayer excitons in the top and bottom bilayers exhibit opposite polarities. Their hybridization forms a superposition state of interlayer exciton, giving rise to a quadrupolar exciton, with an around 12meV energy difference between dipolar exciton and quadrupolar exciton under a net zero electric field. In the presence of moiré coupling, this hybridization further gives rise to a new type of correlated electronic state, hybridized interlayer Mott insulator, in which the correlated holes are shared between the two WSe₂ layers. The unique trilayer moiré system offers a new exciting playground for realizing novel correlated states and manipulating quantum phase transition.