Exciton broadening and band renormalization due to Dexter-like intervalley coupling
Journal article, 2018

A remarkable property of atomically thin transition metal dichalcogenides (TMDs) is the possibility to selectively address single valleys by circularly polarized light. In the context of technological applications, it is very important to understand possible intervalley coupling mechanisms. Here, we show how the Dexter-like intervalley coupling mixes A and B states from opposite valleys leading to a significant broadening γB 1s of the B 1s exciton. The effect is much more pronounced in tungsten-based TMDs, where the coupling excitonic states are quasi-resonant. We calculate a ratio γB B 1s /γA B 1s ≈ 4.0, which is in good agreement with the experimentally measured value of 3.9 ± 0.7. In addition to the broadening effect, the Dexter-like intervalley coupling also leads to a considerable energy renormalization resulting in an increased energetic distance between A 1s and B 1s states.


linear optics

excitonic physics

transition metal dichalcogenides


Dexter interaction


Ivan Bernal

Chalmers, Physics, Condensed Matter Theory

Gunnar Berghäuser

Chalmers, Physics, Condensed Matter Theory

M. Selig

Technische Universität Berlin

Iris Niehues

University of Münster

Robert Schmidt

University of Münster

R. Schneider

University of Münster

P. Tonndorf

University of Münster

Paul Erhart

Chalmers, Physics, Materials and Surface Theory

Steffen Michaelis De Vasconcellos

University of Münster

R. Bratschitsch

University of Münster

A. Knorr

Technische Universität Berlin

Ermin Malic

Chalmers, Physics, Condensed Matter Theory

2D Materials

2053-1583 (eISSN)

Vol. 5 2 025011

Subject Categories

Atom and Molecular Physics and Optics

Other Physics Topics

Condensed Matter Physics



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5/2/2018 7