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arXiv · 1705.10988

Valley Dynamics of Excitons in Monolayer Dichalcogenides

Gerd Plechinger·Philipp Nagler·Ashish Arora·Robert Schmidt·Alexey Chernikov·John Lupton·Rudolf Bratschitsch·Christian Schüller·Tobias Korn
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Abstract

Monolayer transition-metal dichalcogenides (TMDCs) have recently emerged as possible candidates for valleytronic applications, as the spin and valley pseudospin are directly coupled and stabilized by a large spin splitting. In these semiconducting materials, optically excited electron-hole pairs form tightly Coulomb-bound excitons with large binding energies. The selection rules for excitonic transitions allow for direct optical generation of a valley-polarized exciton population using resonant excitation. Here, we investigate the exciton valley dynamics in monolayers of three different TMDCs by means of time-resolved Kerr rotation at low temperatures. We observe pronounced differences in the valley dynamics of tungsten- and molybdenum-based TMDCs, which are directly related to the opposite order of the conduction-band spin splitting in these materials.

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Gerd Plechinger, Philipp Nagler, Ashish Arora, Robert Schmidt, Alexey Chernikov, John Lupton, Rudolf Bratschitsch, Christian Schüller, Tobias Korn. 2017-06-07. Valley Dynamics of Excitons in Monolayer Dichalcogenides. https://doi.org/10.1002/pssr.201700131

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