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arXiv · 1703.06593

Imparity in valley population for single layer transition metal dichalcogenides under elliptical polarization

Parijat Sengupta·Yaohua Tan·Dmitris Pavlidis·Junxia Shi
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Abstract

The illumination of a single-layer transition metal dichalcogenide with an elliptically-polarized light beam is shown to give rise to a differential rate of inter-band carrier excitation between the valence and conduction states around the valley edges, $ K $ and $ K^{'} $. This rate with a linear dependence on the beam ellipticity and inverse of the optical gap manifests as an asymmetric Fermi distribution between the valleys or a non-equilibrium population which under an external field and a Berry curvature induced anomalous velocity results in an externally tunable finite valley Hall current. Surface imperfections that influence the excitation rates are included through the self-consistent Born approximation. Additionally, we show that circular dichroism in the vicinity of the valley edges also exhibits an ellipticity dependence.

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Parijat Sengupta, Yaohua Tan, Dmitris Pavlidis, Junxia Shi. 2017-03-27. Imparity in valley population for single layer transition metal dichalcogenides under elliptical polarization. https://arxiv.org/abs/1703.06593

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