2023, Moiré enhanced potentials in twisted transition metal dichalcogenide trilayers homostructures, Small.
2023, Moiré enhanced potentials in twisted transition metal dichalcogenide trilayers homostructures, Small
Abstract:
The study of Moiré superlattices in van der Waals materials have garnered significant attention due to the potential for revealing novel quantum phenomena arising from the interplay between atomic structure and electronic correlation. The periodic moiré potential generated by Moiré superlattices can impose constraints on the recombination of excitons, leading to the emergence of exotic quantum phenomena such as moiré excitons and flat bands, which have been extensively studied in transition metal dichalcogenide (TMD) structures. However, the impact of the moiré potential modulation on the number of twisted layers has yet to be experimentally explored. Here, we synthesized a twisted WSe2 homotrilayer using a dry-transfer method and investigated the enhancement of the moiré potential with the increasing number of twisted layers. The results of the study revealed the presence of multiple exciton resonances with positive or negative circularly polarized emission in the WSe2 homostructure with small twist angles, which are attributed to the excitonic ground and excited states confined to the moiré potential. The distinct g-factor observed in the magneto-optical spectroscopy was also shown to be a result of the confinement of the exciton in the moiré potential. The moiré potential depths of the twisted bilayer and trilayer homostructures were found to be 111 and 212 meV, respectively, an increase of 91% from the bilayer structure. These findings demonstrate that the depth of the moiré potential can be manipulated by adjusting the number of stacked layers, providing a new method for controllable preparation of moiré potentials and a promising avenue for further exploration into highly correlated quantum phenomena.
Keywords: Moiré superlattices, Moiré excitons, WSe2/WSe2 /WSe2 homotrilayer, Moiré potential
Link: https://onlinelibrary.wiley.com/doi/10.1002/smll.202207988
