Buckling of carbon nanotubes using molecular dynamics simulation: Investigating the effect of boron doping by considering the interaction energy

This study investigates the atomic-scale stability and buckling behavior of boron-doped carbon nanotubes (CNTs) using molecular dynamics simulations. After equilibration in the NVT ensemble, we applied compressive deformation to evaluate the mechanical response and structural evolution during buckling. The kinetic energy profile revealed an initial increase followed by gradual stabilization, with a stable buckled configuration achieved after approximately 30,000 time steps. The maximum kinetic energy (140.58 eV at 5% doping) and corresponding MSD (0.00424 Å 2 ) indicated intense atomic mobility during early deformation. The center-of-mass displacement peaked at approximately 21,300 time steps and converged to 102.23 Å, confirming the formation of a mechanically stable buckled structure. Radial distribution function analysis demonstrated that the first coordination shell remained centered near 1.45 Å before and after buckling, confirming preservation of the covalent bonding network without bond rupture. However, increasing the boron concentration progressively reduced the RDF peak intensity and broadened the higher coordination shells, indicating increased lattice distortion and reduced medium-range ordering. We systematically examined the effect of boron doping concentration (5–30%) on mechanical behavior. Increasing doping enhanced atomic mobility, with the kinetic energy rising to 198.09 eV and the MSD increasing to 0.00613 Å 2 at 30% doping. Nevertheless, stress–displacement analysis revealed monotonic mechanical softening, with peak stress decreasing from approximately 260–270 MPa at 10% doping to nearly 120–130 MPa at 30% doping. The center-of-mass (COM) displacement during buckling exhibited non-monotonic behavior, reaching a maximum value of approximately 103.74 Å at 20% boron doping. This behavior resulted from the competition between the enhanced structural deformability induced by boron incorporation and the progressive reduction in interatomic cohesion at higher dopant concentrations, which weakened the nanotube's overall structural resistance during compressive deformation. Therefore, moderate boron doping optimized buckling amplitude while preserving structural integrity, whereas excessive doping induced lattice disorder and mechanical softening. These findings provide atomic-scale insight into tuning CNT mechanical stability through controlled substitutional doping for nano-mechanical applications.