Molecular Dynamics Study of Anisotropic Shock Response in Mono-and Bicrystalline Boron Nitride Nanosheets: Implications for Shock-Resistant Solid-State Devices

A Chaurasia and A Parashar, ACS APPLIED NANO MATERIALS (2022).

DOI: 10.1021/acsanm.1c04483

In the present article, the anisotropic shock response of a bicrystalline boron nitride nanosheet (BNNS) was studied systematically and comprehensively with the help of a classical mechanics-based molecular dynamics approach. In monocrystal BNNSs, shock loading along the armchair (AC) direction manifested superior resistance capability as compared to the loading along the zigzag (ZZ) direction. Shock loading aligned with the AC direction triggers slip nucleation and growth via compression of the hexagon ring along the ZZ direction. The shock response of bicrystalline BNNSs shows pronounced anisotropy for AC-and ZZ-oriented grain boundaries (GBs). It was revealed from the simulations that critical velocity (u(p)(c)) required to nucleate slip in bicrystalline BNNSs increases with the GB misorientation angle for both AC-and ZZ-oriented GBs; overall, the AC-oriented GBs perform better in resisting shock compression compared to ZZ-oriented GBs. Meta and para position atoms nucleate slip in the AC and ZZ direction, respectively. However, at higher shock loading (u(p) > u(p)(c)), a lower GB misorientation angle in ZZ-oriented GBs exhibits poor shock resistance capability and slip nucleated from the grain interior itself at early stages of the compression. The outcomes of this study provide the physical insights into design of the defective BNNS-based nanolaminates, the substrate for graphene, and solid-state devices (field-effect transistors) with superior mechanical properties against shock loading.

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