Title: Controlled dynamic screening of excitonic complexes in 2D semiconductors,
Abstract: We report a combined theoretical/experimental study of dynamic screening of
excitons in media with frequency-dependent dielectric functions. We develop an
analytical model showing that interparticle interactions in an exciton are
screened in the range of frequencies from zero to the characteristic binding
energy depending on the symmetries and transition energies of that exciton. The
problem of the dynamic screening is then reduced to simply solving the
Schrodinger equation with an effectively frequency-independent potential.
Quantitative predictions of the model are experimentally verified using a test
system: neutral, charged and defect-bound excitons in two-dimensional monolayer
WS2, screened by metallic, liquid, and semiconducting environments. The
screening-induced shifts of the excitonic peaks in photoluminescence spectra
are in good agreement with our model.