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

doi:10.1103/PhysRevB.90.161302

Exciton Valley Dynamics probed by Kerr Rotation in WSe2 Monolayers

Mesoscale and Nanoscale Physics 2014-10-10 v1

Authors: 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.

Keywords

exciton valley dynamics WSe2 monolayers Kerr rotation valley depolarization Coulomb exchange interaction pump-probe spectroscopy

Cite

@article{arxiv.1407.5862,
  title  = {Exciton Valley Dynamics probed by Kerr Rotation in WSe2 Monolayers},
  author = {C. R. Zhu and K. Zhang and M. Glazov and B. Urbaszek and T. Amand and Z. W. Ji and B. L. Liu and X. Marie},
  journal= {arXiv preprint arXiv:1407.5862},
  year   = {2014}
}

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5 pages, 3 figures

Exciton Valley Dynamics probed by Kerr Rotation in WSe2 Monolayers

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