Effect of the Stone–Wales (SW) defect on the response of BNNT to axial tension and compression: a quantum chemical study

Abstract

Using density functional theory, effect of the Stone–Wales (SW) defect on the structural and electronic properties of (6,0) zigzag single-walled boron nitride nanotube (BNNT) under axial tension and compression was investigated at B3LYP/6-31+G(d) level of theory. The calculated binding energy for SW defective BNNT is estimated to be smaller than pristine BNNT. In Stone–Wales defected BNNT (SW–BNNT), the defect region serves as a nucleation site for fraction. It is predicted that the fracture is started from the N–N bond connecting the pentagon and heptagon rings, which is different from fracture mechanism proposed for carbon nanotubes (CNT) with similar location of SW defects. Increase in the energy difference between defective and perfect BNNT, ∆E = E SW − E perfect, was predicted upon axial tension. According to our calculation, band gap energy of the SW–BNNT decreases under axial tension and increases under axial compression. It is predicted that the SW–BNNT and in turn its tensile form are more suitable than perfect one for photoconductivity applications.