In the DFG priority program „2D Materials – Physics of van der Waals [hetero]structures“, our project aims at exploring the moiré physics of twisted TMD heterobilayers, especially the behaviour of interlayer excitons and interlayer-exciton polaritons in heterobilayers with a type-II band alignment, such as MoS2/WS2 or MoSe2/WSe2.
Inducing a small twist angle between the constituing layers results in the emergence of a new moiré superlattice. Interlayer excitons in a moiré lattice perceive the varying stacking order over the moiré unit cell as a deep, trapping moiré potential. The lattice constant of the superlattice can be tuned by the twist angle, see the animation.
Approximating the IXs as bosons and considering the regular underlying lattice potential allows to draw the analogy to Bose-Hubbard models. This gives an understanding about the correlated phases that are accessible by tuning the moiré twist angle.
The project goals are summarized in the following, see also the link.