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arXiv · 1711.08691

Phonon Sidebands in Transition Metal Dichalcogenides

Dominik Christiansen·Malte Selig·Gunnar Berghäuser·Robert Schmidt·Iris Niehues·Robert Schneider·Ashish Arora·Steffen Michaelis de Vasconcellos·Rudolf Bratschitsch·Ermin Malic·Andreas Knorr
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Abstract

Excitons dominate the optical properties of monolayer transition metal dichalcogenides (TMDs). Besides optically accessible bright exciton states, TMDs exhibit also a multitude of optically forbidden dark excitons. Here, we show that efficient exciton-phonon scattering couples bright and dark states and gives rise to an asymmetric excitonic line shape. The observed asymmetry can be traced back to phonon-induced sidebands that are accompanied by a polaron redshift. We present a joint theory-experiment study investigating the microscopic origin of these sidebands in different TMD materials taking into account intra- and intervalley scattering channels opened by optical and acoustic phonons. The gained insights contribute to a better understanding of the optical fingerprint of these technologically promising nanomaterials.

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Dominik Christiansen, Malte Selig, Gunnar Berghäuser, Robert Schmidt, Iris Niehues, Robert Schneider, Ashish Arora, Steffen Michaelis de Vasconcellos, Rudolf Bratschitsch, Ermin Malic, Andreas Knorr. 2017-11-23. Phonon Sidebands in Transition Metal Dichalcogenides. https://doi.org/10.1103/physrevlett.119.187402

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