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Mechanical fracture behavior of defective MoS<sub>2</sub> monolayer

ORAL

Abstract

The mechanical properties, including the strength and toughness, of two-dimensional transition-metal chalcogenides play a major role in applications such as flexible electronic devices. In this work, we studied atomic vacancies induced by helium and gallium-ion beams and their effects on mechanical properties of suspended MoS2 monolayers. Atomic-force microscopy (AFM) tests prove that S and MoSx point defects reduce the stiffness but enhance the fracture toughness of MoS2 monolayers. The deflection and bifurcation of cracks and the atomic structure near the crack edges are revealed by scanning-transmission-electron-microscope (STEM) images. Molecular-dynamics simulations based on classical force fields reproduce the microscopic features observed in experiments. MD simulations further predict that defective MoS2 monolayers remain as brittle as pristine ones. The calculated energy release rate is higher in the presence of point defects, which explains the enhancement of fracture toughness as observed in experiments.

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Presenters

  • Yun-Peng Wang

    School of Physics and Electronics, Central South University, Changsha, China

Authors

  • Yun-Peng Wang

    School of Physics and Electronics, Central South University, Changsha, China

  • Gang Wang

    Southern University of Science and Technology, Department of Physics and Shenzhen Key Laboratory for Advanced Quantum Functional Materials and Devices, Southern University of Science and Technology, China, Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China

  • Gang Wang

    Southern University of Science and Technology, Department of Physics and Shenzhen Key Laboratory for Advanced Quantum Functional Materials and Devices, Southern University of Science and Technology, China, Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China

  • Gang Wang

    Southern University of Science and Technology, Department of Physics and Shenzhen Key Laboratory for Advanced Quantum Functional Materials and Devices, Southern University of Science and Technology, China, Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China

  • Gang Wang

    Southern University of Science and Technology, Department of Physics and Shenzhen Key Laboratory for Advanced Quantum Functional Materials and Devices, Southern University of Science and Technology, China, Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China

  • Sokrates T Pantelides

    Vanderbilt Univ, Department of Physics and Astronomy and Department of Electrical and Computer Engineering, Vanderbilt University, Nashville, TN 37235, USA, Department of Physics, Vanderbilt University, Department of Physics and Astronomy and Department of Electrical and Computer Engineering, Vanderbilt University, Nashville, TN

  • Gang Wang

    Southern University of Science and Technology, Department of Physics and Shenzhen Key Laboratory for Advanced Quantum Functional Materials and Devices, Southern University of Science and Technology, China, Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China