Density functional theory study on the geometrical and electronic structures of a new thinnest boron nanotube

Abstract

Single-walled boron nanotubes (BNTs), which has been synthesized successfully recently, were imagined as duals (hexagonal pyramidal structures) of carbon nanotubes (CNTs) in the literature. In this work, we call attention to the fact that BNTs are not limited to hexagonal pyramidal structures constructed from the so-called Aufbau principle, and alternatively, we propose that the thinnest BNT may be a geometrical analog of the corresponding CNT. As shown by our density functional theory calculations, both the tubular open-end cluster models and the infinitely long tube possess high structural, dynamic, and thermal stability, which should be of interest for attempts at its synthesis. Compared to the energetically most stable isomers of the corresponding clusters, the thinnest BNT might be a metastable structure, and from an electronic view of point, it was predicted to have metallic conductivity like hexagonal pyramidal BNTs predicted previously, in contrast to semiconducting crystalline rhombohedral α- and β-boron.