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Phason-assisted interlayer exciton diffusion in a WSe2/WS2 moiré superlattice

ORAL

Abstract

The moiré potential arising from the relative twist and lattice mismatch in heterobilayers of two-dimensional materials has led to the discovery of novel excitonic species. Twist-angle dependent transport measurements of these interlayer excitons have been reported for WSe2/WS2 heterobilayers [1]. In our experiment, we use time- and spatially resolved spectroscopies to investigate the temperature dependent lifetime and diffusion length of various interlayer excitons in WSe2/WS2 heterobilayers, where the individual monolayers have been aligned to produce long-range moiré superlattices. We observe that the temperature dependent formation of the interlayer exciton is reflected in the overall lifetime and diffusion lengths of exciton species in the WSe2/WS2 heterobilayer. The excitons diffusion is affected by the presence of the moiré trap and increasing the temperature, they acquire enough energy to escape the potential barrier. However, at low temperature the moiré phonons (phasons) allow for non-zero diffusion of the exciton providing enough energy for the exciton to hop from one site to another.

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Publication: [1] Yuan, Long, et al. Nature materials 19.6 (2020): 617-623

Presenters

  • Archana Raja

    Lawrence Berkeley National Laboratory

Authors

  • Antonio Rossi

    Lawrence Berkeley National Laboratory

  • Jonas Zipfel

    Lawrence Berkeley National Laboratory

  • Indrajit Maity

    Imperial College London

  • Luca Francaviglia

    Lawrence Berkeley National Laboratory

  • Monica Lorenzon

    Lawrence Berkeley National Laboratory

  • Mit H Naik

    University of California, Berkeley, University of California at Berkeley and Lawrence Berkeley National Lab, University of California at Berkeley; Lawrence Berkeley National Lab

  • Emma Regan

    University of California, Berkeley

  • Daria Blach

    Purdue University

  • Hasan S Yavas

    Aalto University, Lawrence Berkeley National Laboratory, QuEra Computing Inc, University of Texas at Austin, SLAC - Natl Accelerator Lab

  • Kenji Watanabe

    National Institute for Materials Science, Research Center for Functional Materials, National Institute of Materials Science, Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-044, Japan, NIMS, Research Center for Functional Materials, National Institute for Materials Science, National Institute for Materials Science, Japan, Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Japan, NIMS Japan

  • Takashi Taniguchi

    National Institute for Materials Science, Kyoto Univ, International Center for Materials Nanoarchitectonics, National Institute of Materials Science, Kyoto University, International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-044, Japan, International Center for Materials Nanoarchitectonics, National Institute for Materials Science, National Institute for Materials Science, Japan, National Institute For Materials Science, NIMS, National Institute for Material Science, International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan, NIMS Japan

  • Eli Rotenberg

    Lawrence Berkeley National Laboratory, Advanced Light Source, Lawrence Berkeley National Lab

  • feng wang

    University of California, Berkeley

  • 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

  • Libai Huang

    Purdue University

  • Johannes C Lischner

    Imperial College London

  • Archana Raja

    Lawrence Berkeley National Laboratory

  • Alexander Weber-Bargioni

    Lawrence Berkeley National Laboratory