Single-photon emission
from monolayer transition metal
dichalcogenides
requires the existence of localized, atom-like states within the extended
material. Here, we predict from first-principles the existence of
quantum dots around atomic-scale protrusions, which result from substrate
roughness or particles trapped between layers. Using density functional
theory, we find such deformations to give rise to local membrane stretching
and curvature, which lead to the emergence of gap states. Having enhanced
outer-surface localization, they are prone to mixing with states pertaining
to chalcogen vacancies and adsorbates. If the deformation is sharp,
the conduction band minimum furthermore assumes atomic and valley-mixed
character, potentially enabling quantum light emission. When such
structural defects are arranged in an array, the new states couple
to form energetically separated sub-bands, holding promise for intriguing
superlattice dynamics. All of the observed features are shown to be
closely linked to elastic, deformation-induced intra- and intervalley
scattering processes.