Moiré Enhanced Potentials in Twisted Transition Metal Dichalcogenide Trilayers Homostructures

Abstract

Moiré superlattices in the twisted van der Waals materials have become an excellent platform for exploring new quantum phenomena due to the interaction between atomic structure and electronic correlation. Moiré superlattice can generate periodic moiré potential, which can constrain the recombination of excitons, leading to exotic quantum phenomena, including moiré excitons, flat bands, etc., which have been extensively reported in TMDs structures. However, the effect between the modulating of the moiré potential and the number of twisted layers has not been the subject of experimental research yet. Here we synthesized a twisted trilayer homostructure by a dry-transfer method and the enhancement of the moiré potential by the number of twisted layers is investigated. The moiré potential depths of the twisted bilayer and trilayer homostructure are 111 and 212 meV (increased by 91%), which further demonstrate that the depth of the moiré potential can be controlled by adjusting the number of stacked layers. Enhanced moire potential allows observation of moire excitons at 77 K, which are improved by an order of magnitude bigger than those of other moiré excitons(less than 10 K). Our results provide a new method for controllable preparation of moire potentials and a new avenue for further exploration of highly correlated quantum phenomena.