Boron nanotube structure explored by evolutionary computations

TL;DR

This paper investigates the structure of large-diameter single-wall boron nanotubes using evolutionary algorithms, revealing stable configurations with specific atomic coordination and porosity characteristics.

Contribution

It introduces an evolutionary computation method combined with a Hamiltonian model to explore boron nanotube structures across various densities and sizes.

Findings

Most stable nanotubes have 63% 5-coordinated boron atoms.

Boron nanotubes with low hole density are more stable than flat structures.

Porous tubular structures form at higher hole densities.

Abstract

In this work, we explore the structure of single-wall boron nanotubes with large diameters (about 21~{\AA}) and a broad range of surface densities of atoms. The computations are done using an evolutionary approach combined with a nearest neighbors model Hamiltonian. For the most stable nanotubes, the number of 5-coordinated boron atoms is about $63\%$ of the total number of atoms forming the nanotubes, whereas about $11\%$ are boron vacancies. For hole densities smaller than about 0.22, the boron nanotubes exhibit randomly distributed hexagonal holes and are more stable than a flat stripe structure and a quasi-flat B$_{36}$ cluster. For larger hole densities ($> 0.22$) the boron nanotubes resemble porous tubular structures with hole sizes that depend on the surface densities of boron atoms.