2019/12/15 by Trond I. Andersen, Giovanni Scuri, Andrey Sushko +14
Materials Science · Physics and Astronomy · #2D Materials and Applications #Exciton #Graphene research and applications #Heterojunction #Photoluminescence #Quantum #Stacking #Strong Light-Matter Interactions #Superlattice #cond-mat.mes-hall #van der Waals force
paper · pdf · doi:10.1038/s41563-020-00873-5
25 pages, 4 figures in main text, 4 figures in supplementary materials
arxiv created 2019/12/15 · openalex created_date 2019/12/26 · openalex publication_date 2021/01/04 · arxiv updated 2021/01/27 · openalex updated_date 2026/08/06
Moiré superlattices in twisted van der Waals materials constitute a promising platform for engineering electronic and optical properties. However, a major obstacle to fully understanding these systems and harnessing their potential is the limited ability to correlate the local moiré structure with optical properties. By using a recently developed scanning electron microscopy technique to image twisted WSe2/WSe2 bilayers, we directly correlate increasing moiré periodicity with the emergence of two distinct exciton species. These can be tuned individually through electrostatic gating, and feature different valley coherence properties. Our observations can be understood as resulting from an array of two intralayer exciton species residing in alternating locations in the superlattice, and illuminate the influence of the moiré potential on lateral exciton motion. They open up new avenues for controlling exciton arrays in twisted TMDs, with applications in quantum optoelectronics and explorations of novel many body systems.