Exciton Superposition across Moire States in a Semiconducting Moire Superlattice

The moire lattice of trilayer WSe2 and monolayer WS2 host interlayer excitons localized at different moire sites. Using an electric field, the authors tune the superposition between two moire sites via hybridization with intralayer excitons in WSe2. Moire superlattices of semiconducting transition metal dichalcogenides enable unprecedented spatial control of electron wavefunctions, leading to emerging quantum states. The breaking of translational symmetry further introduces a new degree of freedom: high symmetry moire sites of energy minima behaving as spatially separated quantum dots. We demonstrate the superposition between two moire sites by constructing a trilayer WSe2/monolayer WS2 moire heterojunction. The two moire sites in the first layer WSe2 interfacing WS2 allow the formation of two different interlayer excitons, with the hole residing in either moire site of the first layer WSe2 and the electron in the third layer WSe2. An electric field can drive the hybridization of either of the interlayer excitons with the intralayer excitons in the third WSe2 layer, realizing the continuous tuning of interlayer exciton hopping between two moire sites and a superposition of the two interlayer excitons, distinctively different from the natural trilayer WSe2.