Many-body interactions and exciton complexes in a layered semiconductor

ORAL

Abstract

Due to their heavy carrier mass and gate tunability, two-dimensional semiconductors are an exciting platform to study the interplay between many-body effects and exciton physics. In particular, the family of III-VI metal monochalcogenides stems out due to its attractive optical properties and flat valence band dispersion. The influence of such singularity in 2D semiconductors remains largely unexplored, mainly due to difficulties in the fabrication that usually yield non-reproducible results. Here, we employ photoluminescence spectroscopy of charge-tunable excitons in few-layer metal monochalcogenides to probe many-body interactions at the flat band. Furthermore, we provide a reliable marker for the flat band position, to corroborate our interpretation. Our results pave the way for a reproducible and potentially manufacturable device to study the effects of flat-band physics without the need for a twist-angle in the heterostack.

*We acknowledge support from Swiss National Science Foundation (grant nos. 175822, 177007 and 164015) the European Union's Horizon 2020 research and innovation program under grant agreements 785219 and 881603 (Graphene Flagship Core 2 and Core 3). K.W. and T.T. acknowledge support from the Elemental Strategy Initiative conducted by the MEXT, Japan (Grant Number JPMXP0112101001) and JSPS KAKENHI (Grant Numbers JP19H05790 and JP20H00354). E. M. acknowledges funding from Deutsche Forschungsgemeinschaft via CRC 1083 and the Europe Unions Horizon 2020 research and innovation program under grant agreement No. 881603 (Graphene Flagship).

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Publication: Pasquale, G., Sun, Z., Cernevics, K., Perea-Causin, R., Tagarelli, F., Watanabe, K., Taniguchi, T., Malic, E., Yazyev, O.V. and Kis, A., 2022. Flat-band-induced many-body interactions and exciton complexes in a layered semiconductor. arXiv preprint arXiv:2207.13472.

Presenters

  • Gabriele Pasquale

    • EPFL

Authors

  • Gabriele Pasquale

    • EPFL

  • ZHE SUN

    • Ecole Polytechnique Federale De Lausanne
    • EPFL

  • Kristians Cernevics

    • Ecole Polytechnique Federale de Lausanne

  • Raul Perea-Causin

    • Chalmers University
    • Chalmers University of Technology

  • Fedele Tagarelli

    • Ecole Polytechnique Federale de Lausanne

  • Edoardo Lopriore

    • Ecole Polytechnique Federale de Lausanne

  • 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

  • Ermin Malic

    • Philipps-Universität Marburg

  • Oleg V Yazyev

    • Ecole Polytechnique Federale de Lausanne

  • Andras Kis

    • Ecole Polytechnique Federale de Lausanne