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The optical evidence of atomic reconstruction in twisted bilayer MoS<sub>2</sub>

ORAL

Abstract

In two-dimensional materials, Moiré superlattices formed by stacking two monolayers with lattice constant mismatch or rotational misalignment have been widely used to manipulate their electronic and optical properties. Here, we employ low-frequency Raman measurements and DFT calculations to demonstrate atomic reconstruction in the MoS2 homobilayer with a small twist angle (θ). For 0°＜θ≤3.5°, only interlayer Raman mode of 3R stacking with stable peak position is presented, indicating the overwhelming expansion of stable stacking in small twist angle due to structural relaxation. For 3.5°＜θ≤6°, the small Moiré supercell with weak relaxation results in mixed in-plane and out-of-plane vibrations. The shear mode quickly disappears with an increasing twist angle, while mixed breathing modes are observed. Our work provides a novel strategy to understand and monitor the evolution of structural relaxation in moiré superlattices in two-dimensional van der Waals materials.

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Presenters

  • Jiamin Quan

    Physics, University of Texas at Austin, Department of Physics, The University of Texas at Austin, University of Texas at Austin, Department of Physics, Complex Quantum Systems, and Texas Materials Institutes, University of Texas at Austin

Authors

  • Jiamin Quan

    Physics, University of Texas at Austin, Department of Physics, The University of Texas at Austin, University of Texas at Austin, Department of Physics, Complex Quantum Systems, and Texas Materials Institutes, University of Texas at Austin

  • Lukas Linhart

    Vienna University of Technology

  • Miao-Ling Lin

    Chinese Academy of Sciences, State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors,Chinese Academy of Sciences, Beijing 100083, China

  • Chun Yuan Wang

    Physics, University of Texas at Austin, University of Texas at Austin

  • Wei-Ting Hsu

    Department of Physics, The University of Texas at Austin, University of Texas at Austin

  • Junho Choi

    Physics, University of Texas at Austin, University of Texas at Austin, Department of Physics, Complex Quantum Systems, and Texas Materials Institutes, University of Texas at Austin

  • Carter Young

    Department of Physics, University of Texas at Austin, University of Texas at Austin, Department of Physics, Complex Quantum Systems, and Texas Materials Institutes, University of Texas at Austin

  • Takashi Taniguchi

    National Institute for Materials Science, National Institute for Material Science, Japan, National Institute of Material Science in Tsukuba, Kyoto Univ, Chemical Engineering, Kyoto University, Advanced Materials Laboratory, National Institute for Materials Science, National Institute of Materials Science (NIMS), National Institute of Materials Science, Japan, Kyoto University

  • Chih-Kang Shih

    University of Texas at Austin, Physics, University of Texas at Austin, Department of Physics, The University of Texas at Austin

  • Allan MacDonald

    University of Texas at Austin, Physics, University of Texas at Austin, Department of Physics, University of Texas at Austin, Department of Physics, The University of Texas at Austin

  • Ping-Heng Tan

    Chinese Academy of Sciences, State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors,Chinese Academy of Sciences, Beijing 100083, China, State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences

  • Florian M Libisch

    Vienna University of Technology

  • Xiaoqin (Elaine) Li

    Physics, University of Texas at Austin, Department of Physics, The University of Texas at Austin, Department of Physics, University of Texas at Austin, University of Texas at Austin, Department of Physics, Complex Quantum Systems, and Texas Materials Institutes, University of Texas at Austin