Dresden 2026 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 20: Poster I
HL 20.15: Poster
Dienstag, 10. März 2026, 18:00–20:00, P1
Many-body effects and intervalley coupling mechanisms in monolayer transition metal dichalcogenides — •Oleg Dogadov1,2, Henry Mittenzwey3, Thomas Deckert4, Micol Bertolotti2, Daniele Brida4, Giulio Cerullo2,5, Andreas Knorr3, and Stefano Dal Conte2 — 1Fritz Haber Institute, Berlin, Germany — 2Politecnico di Milano, Milan, Italy — 3Technische Universität Berlin, Berlin, Germany — 4University of Luxembourg, Luxembourg — 5CNR-IFN Milan, Italy
The strongly bound excitons and the spin-valley locking effect make monolayer (1L) transition metal dichalcogenides (TMDs) an ideal platform to study intra- and intervalley many-body effects. Despite extensive studies conducted during the last years, a unified description of the competing many-body interactions and intervalley coupling processes in 1L-TMDs is lacking. Here, we apply broadband helicity-resolved transient absorption spectroscopy combined with a microscopic theory based on the excitonic Bloch equations to investigate coherent optical response and valley polarization dynamics in 1L-WSe2. We unambiguously unravel competing valley-dependent contributions of two- and four-particle correlations to the coherent optical response of the studied material. By exploring the valley (de)polarization dynamics, we dissect the roles of individual intervalley coupling mechanisms, including Coulomb exchange and Dexter-like interaction, as well as phonon-assisted scattering, providing a consistent picture of the processes governing spin-valley dynamics in 1L-TMDs.
Keywords: transition metal dichalcogenides; transient absorption spectroscopy; many-body interactions; valley dynamics