# Valley Dynamics of Excitons in Monolayer Dichalcogenides

## TL;DR

This study investigates the valley dynamics of excitons in monolayer TMDCs using time-resolved Kerr rotation, revealing material-dependent differences linked to conduction-band spin splitting.

## Contribution

It provides new insights into exciton valley dynamics in different TMDC monolayers through experimental time-resolved measurements.

## Key findings

- Distinct valley relaxation times in tungsten- and molybdenum-based TMDCs
- Valley dynamics are influenced by conduction-band spin splitting
- Experimental evidence of valley polarization behavior

## 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.