Stability and electronic properties of small BN nanotubes

TL;DR

This study investigates the stability and electronic properties of small boron nitride nanotubes using computational methods, revealing their potential as semiconductors and the effects of encapsulation on their electronic structure.

Contribution

It provides new insights into the stability, electronic structure, and effects of encapsulation of small BN nanotubes, which were not extensively studied before.

Findings

Certain small BNNTs are stable at room temperature.

Encapsulation in larger BNNTs stabilizes small BNNTs.

Electronic properties depend strongly on chirality and diameter.

Abstract

We report the stability and electronic structures of the boron nitride nanotubes (BNNTs) with diameters below 4 A by semi-empirical quantum mechanical molecular dynamics simulations and ab initio calculations. Among them (3,0), (3,1), (2,2), (4,0), (4,1) and (3,2) BNNTs can be stable well over room temperature. These small BNNTs become globally stable when encapsulated in a larger BNNT. It is found that the energy gaps and work functions of these small BNNTs are strongly dependent on their chirality and diameters. The small zigzag BNNTs become desirable semiconductors and have peculiar distribution of nearly free electron states due to strong hybridization effect. When such a small BNNT is inserted in a larger one, the energy gap of the formed double-walled BNNT can even be much reduced due to the coupled effect of wall buckling difference and NFE-pi hybridization.