Vortrag im Rahmen der Chemisch Physikalischen Gesellschaft
Mechanical strain is a powerful tuning knob for excitons. We present a multiscale tightbinding simulation for the optical spectra of WSe2 under nonuniform strain in the presence of point defects [1]. Under the application of strain, conduction-band states are brought into energetic resonance with localized defect orbitals, forming a new hybrid state that inherits the properties of the constituent species. We compare our model to photoluminescence measurements of these fragile many-body states on pristine suspended WSe2 kept at cryogenic temperatures [2]. The characteristics of the hybridized state, including an order-of-magnitude enhanced light/matter coupling, avoidedcrossing energy shifts, and strain tunability of many-body interactions, all fit to our simulation.
Our results suggest such hybridized excitons may play a critical role in the operation of single quantum emitters based on WSe2. Furthermore, the techniques we developed may be used to fingerprint unidentified excitonic states.
[1] L. Linhart et al., Phys. Rev. Lett. 123, 146401 (2019)
[2] H. Hernandez Lopez et al., Nature Comm. 13, 7691 (2022)
