| GUO Yi-bo,PANG Hua,LIU Da-meng.Modulation of Transverse Stress Field on Atomic-scale Friction[J],49(1):187-193 |
| Modulation of Transverse Stress Field on Atomic-scale Friction |
| Received:April 21, 2019 Revised:January 20, 2020 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2020.01.022 |
| KeyWord:atomic-scale friction stress field modulation 2D materials PT model friction energy dissipation effective stiffness surface potential barrier |
| Author | Institution |
| GUO Yi-bo |
State Key Laboratory of Tribology, Tsinghua University, Beijing , China |
| PANG Hua |
State Key Laboratory of Tribology, Tsinghua University, Beijing , China |
| LIU Da-meng |
State Key Laboratory of Tribology, Tsinghua University, Beijing , China |
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| Abstract: |
| To explore the modulation of transverse strain field on friction energy dissipation in atomic scale, in this paper, monolayer to multilayer ultrathin MoS2 specimens were prepared by the mechanical cleavage technique. The layer number of MoS2 was identified with optical microscope, low-frequency Raman and high-frequency Raman. The atomic scale fraction experiments were carried out on monolayer to multilayer MoS2 to explore modulation of lateral stress field on the atomic dimension fraction parameters and fraction energy dissipation. Based on the independent oscillator model, the influences of two important parameters i.e. effective stiffness and surface potential barrier on the atomic-scale friction were investigated and the friction energy dissipation of MoS2 in atomic scale was calculated. Under no strain, when the layer number of MoS2 increased from monolayer to multilayer, the effective stiffness and surface potential barrier increased from 2.92 N/m to 7.41 N/m and from 0.36 eV to 2.94 eV, respectively. The average frictional force of monolayer MoS2 was the largest, that of bilayer MoS2 was the second, and that of multilayer MoS2 was the smallest. When the strain increased from 0 to 10.6%, the effective stiffness and surface potential barrier of monolayer MoS2 increased from 2.92 N/m to 12.03 N/m and from 0.36 eV to 2.94 eV, respectively. However, the effect of strain field on surface potential barrier modulation was stronger, which leaded to a positive correlation between the relative barrier and the strain. With the increase of the strain field, the friction energy dissipation at atomic scale increased; and when the stress field first acted on MoS2, there was a significant increase in the friction energy dissipation. The friction energy dissipation of monolayer MoS2 increased from 1.3×10–13 J without strain to 1.9×10–12 J with strain of 0.53%. Studying friction energy dissipation not only helps to explore the origin of friction, but also can realize the modulation of frictional energy dissipation. This work can promote the study of atomic-scale energy dissipation and provide a new direction for the modulation of frictional energy dissipation. |
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