A DFT study of elastic and structural properties of (3,3) boron nitride nanotube under external electric field

• Density functional theory investigation of elastic and structural characteristics of armchair BNNT under external electric field.
• Obtaining the new bond lengths and atomic positions of BNNT subjected to external homogeneous electric field.
• Comparison between the rate changes of radius, equilibrium strain energy and Young's modulus by increasing the magnitude of electric field.

The aim of present study is to investigate the effect of external electric field on the elastic and structural properties of a (3,3) armchair boron nitride nanotube (BNNT). To accomplish this purpose, the density functional theory (DFT) within the generalized gradient approximation (GGA) framework is employed. The calculations are performed employing Plane-Wave basis set and pseudopotentials. The structural and elastic properties of armchair BNNT are predicted in the presence of electric field parallel and perpendicular to tube axis. The homogeneous electric fields are applied to BNNT on the basis of the estimated optimized wave function. The obtained results indicate that in contrast to the perpendicular field, the external electric field along tube axis causes considerable changes in the value of bond length and atomic positions. Moreover, it is found that by applying electric field along tube axis direction, Young’s modulus of BNNT decreases about 13% compared to that in the absence of external electric field, which means a significant reduction in the axial stiffness of BNNT.