Valley Dynamics of Excitons in Monolayer Dichalcogenides

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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Cited by in corpus (8)

• Spin-phonon relaxation from a universal \emph{ab initio} density-matrix approach
• Quenching of Intervalley Exchange Coupling in the Presence of Momentum-Dark States in TMDCs
• Spin accumulation and dynamics in inversion-symmetric van der Waals crystals
• Theory of the Coherent Response of Magneto-Excitons and Magneto-Biexcitons in Monolayer Transition Metal Dichalcogenides
• Nonexponential photoluminescence dynamics in an inhomogeneous ensemble of excitons in WSe${}_2$ monolayers
• Dissecting intervalley coupling mechanisms in monolayer transition metal dichalcogenides
• Pump-driven opto-magnetic properties in semiconducting transition-metal dichalcogenides: an analytical model
• Two-color Kerr microscopy of two-dimensional materials with sub-picosecond time resolution