Disorder-induced broadening of excitonic resonances in transition metal dichalcogenides
Journal article, 2019

The presence of impurities and disorder has an important impact on the optical response of monolayer transition metal dichalcogenides (TMDs). Here, we investigate elastic exciton-impurity scattering and its influence on the linewidth of excitonic resonances in different TMD materials. We derive an analytic expression for the linewidth broadening within the density matrix formalism. We find that the exciton linewidth increases for states up to the 3s exciton due to the scattering with impurities. For higher states, the impurity contribution decreases, reflecting the reduced scattering cross section. Furthermore, we reveal that the scattering efficiency is the largest for transitions between s and p exciton states. Finally, different TMDs show generally a similar behavior. The quantitatively smaller broadening in tungsten-based TMDs can be ascribed to their smaller effective masses resulting in a less efficient scattering.

Author

Magdulin Dwedari

University of Duisburg-Essen

Samuel Brem

Chalmers, Physics, Condensed Matter Theory

Maja Feierabend

Chalmers, Physics, Condensed Matter Theory

Ermin Malic

Chalmers, Physics, Condensed Matter Theory

PHYSICAL REVIEW MATERIALS

2475-9953 (ISSN)

Vol. 3 7 074004

Subject Categories

Atom and Molecular Physics and Optics

Condensed Matter Physics

DOI

10.1103/PhysRevMaterials.3.074004

More information

Latest update

4/20/2020