Trion valley coherence in monolayer transition metal dichalcogenides

ORAL

Abstract

Excitons and trions in monolayer transition metal dichalcogenides are formed at the boundary of the Brillouin zone at two inequivalent K and K’ valleys. Because of the valley contrasting optical selection rule, excitons and trions can be preferentially created using in a selected valley using light with a particular circular polariztion. Valley coherence — the coherent superposition between the excitonic states in the two valleys can be generated by a linearly polarized excitation. Exciton valley coherence has been detected as linearly polarized PL emission. However, the same method is not applicable to trions due to the spin-photon entanglement. With two-dimnensional Fourier transform spectroscopy, we explicitly measure the nonradiative exciton and trion valley coherence. Unlike exction, whose valley coherent time is limited by intrinsic fast population decay and electron-hole exchange interaction, our result shows that trion valley coherent time is limited by intra-valley pure dephasing processes.

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Presenters

  • Kai Hao

    Department of Physics, Univerisity of Texas at Austin

Authors

  • Kai Hao

    Department of Physics, Univerisity of Texas at Austin

  • Lixiang Xu

    Department of Physics, Univerisity of Texas at Austin

  • Fengcheng Wu

    Argonne National Laboratory, Department of Physics, Univerisity of Texas at Austin, Argonne National Lab

  • Philipp Nagler

    Department of Physics, University of Regensburg

  • Kha Tran

    Department of Physics, Univerisity of Texas at Austin, Department of Physics, Univ of Texas, Austin

  • Xin Ma

    Department of Physics, Univerisity of Texas at Austin

  • Christian Schüller

    Institut für Experimentelle und Angewandte Physik, Universität Regensburg, Department of Physics, University of Regensburg

  • Tobias Korn

    Institut für Experimentelle und Angewandte Physik, Universität Regensburg, Department of Physics, University of Regensburg

  • Allan MacDonald

    Physics department, University of Texas at Austin, Physics, University of Texas, Austin, Department of Physics, The University of Texas at Austin, Physics , Univ of Texas, Austin, Univ of Texas at Austin, Physics, The University of Texas at Austin, Department of Physics, Univerisity of Texas at Austin, The University of Texas at Austin, University of Texas

  • Galan Moody

    National Institute of Standards & Technology

  • Xiaoqin (Elaine) Li

    University of Texas at Austin, Department of Physics, Univerisity of Texas at Austin, Department of Physics, Univ of Texas, Austin, Univ of Texas, Austin