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arXiv · 1407.5862

Exciton Valley Dynamics probed by Kerr Rotation in WSe2 Monolayers

C. R. Zhu·K. Zhang·M. Glazov·B. Urbaszek·T. Amand·Z. W. Ji·B. L. Liu·X. Marie
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Abstract

We have experimentally studied the pump-probe Kerr rotation dynamics in WSe$_2$ monolayers. This yields a direct measurement of the exciton valley depolarization time $\tau_v$. At T=4K, we find $\tau_v\approx 6$ps, a fast relaxation time resulting from the strong electron-hole Coulomb exchange interaction in bright excitons. The exciton valley depolarization time decreases significantly when the lattice temperature increases with $\tau_v$ being as short as 1.5ps at 125K. The temperature dependence is well explained by the developed theory taking into account the exchange interaction and a fast exciton scattering time on short-range potentials.

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C. R. Zhu, K. Zhang, M. Glazov, B. Urbaszek, T. Amand, Z. W. Ji, B. L. Liu, X. Marie. 2014-07-22. Exciton Valley Dynamics probed by Kerr Rotation in WSe2 Monolayers. https://doi.org/10.1103/physrevb.90.161302

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