Disorder-dependent valley properties in monolayer WSe2

We investigate the effect on disorder potential on exciton valley polarization and valley coherence in monolayer WSe2. By analyzing polarization properties of photoluminescence, the valley coherence (VC) and valley polarization (VP) is quantified across the inhomogeneously broadened exciton resonance. We find that disorder plays a critical role in the exciton VC, while minimally affecting VP. For different monolayer samples with disorder characterized by their Stokes Shift (SS), VC decreases in samples with higher SS while VP again remains unchanged. These two methods consistently demonstrate that VC as defined by the degree of linearly polarized photoluminescence is more sensitive to disorder potential, motivating further theoretical studies.