Molecular Dynamics Study on the Mechanical Properties of Bilayer Silicon Carbide.

The advent of bilayer silicon carbide as a critical two-dimensional material has opened up a range of potential applications in various fields. The field of nanoelectronics and nanomechanical systems is distinguished by its exceptional mechanical robustness, yet the combined effects of environmental and structural factors on its mechanical integrity remain poorly understood. Molecular dynamics simulations are used in this study to systematically examine the tensile response of bilayer SiC across a range of strain rates, temperatures, vacancy concentrations, and pre-existing crack lengths. Results indicate that mechanical properties converge at a system size of 18,144 atoms, ensuring computational efficiency. Increasing strain rate enhances strength and toughness by suppressing atomic relaxation, while elevated temperature induces thermal softening, reducing failure strain and strength by up to 50% at 900 K. Vacancy defects drastically degrade performance, with 3% concentration causing over 70% toughness loss, and crack propagation follows Griffith-type brittle fracture, where the zigzag direction exhibits superior resistance compared to the armchair orientation. These findings highlight the sensitivity of bilayer SiC to defects and environmental conditions, providing critical insights for designing reliable SiC-based nanodevices.