Probing the interplay of interactions, screening and strain in monolayer MoS2 via self-intercalation

Controlling many-body interactions in two-dimensional systems remains a formidable task from the perspective of both fundamental physics and application. Here, we explore remarkable electronic structure alterations of MoS2 monolayer islands on graphene on Ir(111) induced by non-invasive self-intercalation. This introduces significant differences in morphology and strain of MoS2 as a result of the modified interaction with the substrate. Consequently, considerable changes of the band gap and non-rigid electronic shifts of valleys are detected, which are a combined effect of the screening of the many-body interactions and strain in MoS2. Furthermore, theory shows that each substrate leaves a unique stamp on the electronic structure of two-dimensional material in terms of those two parameters, restricted by their correlation.