Crystal orientation-dependent mechanical property and structural phase transition of monolayer molybdenum disulfide

QL Xiong and T Kitamura and ZH Li, JOURNAL OF APPLIED PHYSICS, 122, 135105 (2017).

DOI: 10.1063/1.4996941

By performing molecular dynamics simulations, we investigate the mechanical property and structural phase transition in monolayer molybdenum disulfide (MoS2) with different crystal orientations under uniaxial tensions systematically. The results show that both the mechanical property and structural phase transition are strongly dependent on the crystal orientation, specifically, for some crystal orientation angles lower than about 20 degrees, the structural phase transition takes place with the plastic deformation; for other crystal orientation angles, plastic deformation cannot occur. Further studies have found that plastic deformation results from irreversible changes of the angles between the bonds, rather than the variation of bond length. Young's modulus increases while ultimate strength and fracture strain decrease with the increase of the crystal orientation angle. The critical strain at which the first structural phase transition occurs increases with the increase of the crystal orientation angle. The plastic deformation and the irreversible structural transition almost linearly increase with the decrease of the crystal orientation angle. Published by AIP Publishing.

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