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Light-induced band asymmetries seen by trARPES and their excitonic origin

ORAL

Abstract

We studied photoexcited band structure and ultrafast phenomena in bulk MoS2 by using extreme-UV time- and angle-resolved photoemission spectroscopy (XUV-trARPES). We observed a light-induced transient spectral signature near valence band maximum with explicit asymmetric distributions in energy and momentum, featuring an unusual two-component decay behavior. We conducted theoretical calculations to understand these observations. We found that the excitonic correlations between electrons and holes play the critical role in understanding these light-induced band asymmetries consistently in energy, momentum, and time. Our work provides a new frame for studying ultrafast excitonic phenomena in optically dark materials, such as bulk semiconductors and excitonic insulators, by using photoelectron spectroscopy.

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Presenters

  • Yi Lin

    Lawrence Berkeley National Laboratory

Authors

  • Yi Lin

    Lawrence Berkeley National Laboratory

  • Yang-hao Chan

    Academia Sinica, Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan, Institute of Atomic and Molecular Sciences, Academia Sinica, Lawrence Berkeley National Laboratory

  • Woojoo Lee

    University of Chicago

  • Chih-Kang Shih

    University of Texas at Austin

  • Steven G Louie

    University of California at Berkeley, University of California, Berkeley, University Of California, Berkeley, University of California at Berkeley and Lawrence Berkeley National Lab, University of California at Berkeley; Lawrence Berkeley National Lab, UC Berkeley, University of California at Berkeley, and Lawrence Berkeley National Laboratory, UC berkeley, Lawrence Berkeley National Laboratory, Physics Department, UC Berkeley and Lawrence Berkeley National Lab, Department of Physics, University of California at Berkeley and Materials Sciences Division, Lawrence Berkeley National Laboratory, LBNL & UC Berkeley

  • Alessandra Lanzara

    University of California, Berkeley