2017/03/20 by Parijat Sengupta, Yao‐Hua Tan, Sengupta, Parijat +5
Materials Science · Physics and Astronomy · #2D Materials and Applications #Quantum Dots Synthesis And Properties #Spectroscopy and Quantum Chemical Studies
paper · pdf · doi:10.48550/arxiv.1703.06593
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.