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Momentum-resolved study of dark excitons in 2D semiconductors by TR-ARPES

ORAL

Abstract

Excitons - quasiparticles formed by coulomb-bounded electron-hole pairs, play a key role in the optical response of 2D semiconductors. In Transition Metal Dichalcogenides – prototypical 2D semiconductors, a complex excitonic landscape exists, including a significant population of spin- or momentum- forbidden dark excitons. While dark excitons are generally invisible to light, they can be directly imaged using time- and angle- resolved photoemission spectroscopy (TR-ARPES) [1,2]. Here, we directly image the wavefunctions of the momentum- and spin-dark excitons and understand the impact of the electron-hole exchange interaction on their size and binding energy.

[1] J. Madéo et al., Directly Visualizing the Momentum-Forbidden Dark Excitons and Their Dynamics in Atomically Thin Semiconductors, Science 370, 1199 (2020).

[2] M. K. L. Man et al., Experimental Measurement of the Intrinsic Excitonic Wave Function, Science Advances 7, eabg0192 (2021).

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Presenters

  • Xing Zhu

    Okinawa Institute of Science & Technology

Authors

  • Xing Zhu

    Okinawa Institute of Science & Technology

  • David R Bacon

    Okinawa Institute of Science & Technology

  • Vivek Pareek

    Okinawa Institute of Science & Technology

  • Julien Madéo

    Okinawa Institute of Science & Technology, Okinawa Institute of Science and Technology

  • Kenji Watanabe

    National Institute for Materials Science, NIMS, Research Center for Functional Materials, National Institute for Materials Science, Research Center for Electronic and Optical Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan, Research Center for Functional Materials, National Institute of Material Science, Tsukuba, Japan, National Institute of Materials Science, Advanced Materials Laboratory, National Institute for Materials Science

  • Takashi Taniguchi

    National Institute for Materials Science, International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Research Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan, International Center for Materials Nanoarchitectonics, National Institute of Material Science, Tsukuba, Japan, Advanced Materials Laboratory, National Institute for Materials Science

  • Michael. K. L. Man

    Okinawa Institute of Science & Technology, Okinawa Institute of Science and Technology

  • Mit H. Naik

    University of California, Berkeley, University of Texas at Austin

  • Keshav M Dani

    Okinawa Institute of Science & Technology