Exciton broadening and band renormalization due to Dexter-like intervalley coupling
Artikel i vetenskaplig tidskrift, 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.

valleytronics

linear optics

excitonic physics

transition metal dichalcogenides

spintronics

Dexter interaction

Författare

Ivan Bernal

Chalmers, Fysik, Kondenserade materiens teori

Gunnar Berghäuser

Chalmers, Fysik, Kondenserade materiens teori

M. Selig

Technische Universität Berlin

Iris Niehues

Universität Münster

Robert Schmidt

Universität Münster

R. Schneider

Universität Münster

P. Tonndorf

Universität Münster

Paul Erhart

Chalmers, Fysik, Material- och ytteori

Steffen Michaelis De Vasconcellos

Universität Münster

R. Bratschitsch

Universität Münster

A. Knorr

Technische Universität Berlin

Ermin Malic

Chalmers, Fysik, Kondenserade materiens teori

2D Materials

2053-1583 (eISSN)

Vol. 5 025011

Ämneskategorier

Atom- och molekylfysik och optik

Annan fysik

Den kondenserade materiens fysik

DOI

10.1088/2053-1583/aaaa8b