Chirality, temperature, and vacancy effects on mechanical behavior of monolayer zinc-sulfide

ASMJ Islam and MS Hasan and MS Islam and J Park, COMPUTATIONAL MATERIALS SCIENCE, 200, 110824 (2021).

DOI: 10.1016/j.commatsci.2021.110824

Structural reliability is one of the most fundamental disquiets for realizing future nanoelectromechanical systems (NEMS). Of late, atomically thin two-dimensional zinc sulfide (2D-ZnS) shows great potential for advanced NEMS and a substitute to graphene and transition metal di-chalcogenides because of its exceptional optical and electronic properties. Here, we systematically explore the impacts of temperature (100-700 K) and vacancy defects (bi and point vacancies) with a concentration of 0.3%-1.0% on the tensile mechanical behavior such as fracture strength, elastic modulus as well as fracture strain of 2D-ZnS through molecular dynamics simulation. To expose the fracture mechanism quantitatively, the rupturing phenomenon at different temperature and vacancy concentrations for bi vacancy and point vacancy defects is also explored. The mechanical behavior with different sheet area and loading rate are also exposed. At room temperature, fracture stress of similar to 40.94 GPa and an elastic modulus of similar to 313.66 GPa along the armchair direction were determined, which is about similar to 3.65% and similar to 2.75% greater than the zigzag oriented fracture strength and elastic modulus, respectively. The point vacancy makes the mechanical strength decline more rapidly than the bi vacancy because of its more significant regularity breakdown effect. We also find that 2D-ZnS is less sensitive to sheet area and strain rate compared to temperature and vacancy defects. The in-depth analysis on mechanical properties explored here would be beneficial in controlling the tensile mechanical behavior of 2D-ZnS for its applications in next-generation NEMS and nanodevices.

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