Exciton Valley Dynamics probed by Kerr Rotation in WSe2 Monolayers

2014/07/22 by C. R. Zhu, K. Zhang, M. Glazov +5 · 2 citations
Physics and Astronomy · #cond-mat.mes-hall

paper · pdf · doi:10.1103/physrevb.90.161302

published as Physical Review B 90, 161302(R) (2014) · 5 pages, 3 figures

arxiv created 2014/07/22 · arxiv updated 2014/10/10

Abstract

We have experimentally studied the pump-probe Kerr rotation dynamics in WSe₂ monolayers. This yields a direct measurement of the exciton valley depolarization time τ_v. At T=4K, we find τ_v≈ 6ps, 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 τ_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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• Spin-Valley Relaxation of Rydberg Excitons
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