Ab initio study of structural properties and inter-wall distances of double-walled BN nanotubes

Abstract

The structural, stability, and electronic properties and optimized inter-wall distances of double-walled boron nitride nanotubes (DWBNNTs) are investigated based on density functional theory (DFT) with the SIESTA code. The computations are done on the zigzag ([Formula: see text],0)@([Formula: see text],0) DWBNNTs with chirality of ([Formula: see text], 7 and [Formula: see text]–18) and the armchair ([Formula: see text] with chirality of ([Formula: see text], 6 and [Formula: see text]–15). The calculated binding and formation energies revealed that the armchair and the zigzag DWBNNTs with chirality differences of ([Formula: see text] and 9) ([Formula: see text]), ([Formula: see text]) and inter-layer spacing of about 4.22Å and 3.62Å are the best favorable nanotubes, respectively. Analyzing the electronic structures revealed that all considered armchair and zigzag BNNTs are semiconductors. Furthermore, it is concluded that with increasing diameters of the tubes and the spaces between walls, the value of the band gap rises, and the change process is almost constant at larger distances between the walls. Also, compared to single-walled nanotubes, DWBNNTs have a narrower bandgap. Future empirical investigations can definitely benefit from the implications of this research.