Octagonal Family of Monolayers, Bulk and Nanotubes

TL;DR

This paper introduces a new class of octagonally symmetric 2D monolayers, bulk structures, and nanotubes, exploring their stability, electronic properties, and potential for technological applications through computational design.

Contribution

It computationally designs and analyzes the stability and electronic structures of a novel octagonal family of monolayers, bulk phases, and nanotubes, revealing their diverse bonding and phase properties.

Findings

Binary o-MLs exhibit mixed ionic and covalent bonding.

Patterned hybrid o-MLs can be metallic or insulating.

Stacked o-MLs form stable bulk phases and nanotubes.

Abstract

A new class of tetragonally symmetric 2D octagonal family of monolayers (o-MLs) has emerged recently and demands understanding at the fundamental level. o-MLs of metal nitride and carbide family (BN, AlN, GaN, GeC, SiC) along with C and BP are computationally designed and their stability and electronic structure are investigated. These binary o-MLs show mixed ionic and covalent bonding with the hybridized p states dominating the electronic structure around the Fermi level. Geometric and structural similarity of o-C and o-BN has been exploited to form patterned hybrid o-MLs ranging from metallic to insulating phases. Stacking of zigzag buckled o-MLs results in stable body centered tetragonal (bct)-bulk phase that is suitable for most materials from group IV, III-V and II-VI. Vertically cut chunks of o-BN and o-C bulk or stacking of o-rings, unlike rolling of hexagonal (h)-ML, provide a plausible way to form very thin o-nanotubes (o-NT). Confined and bulk structures formed with an octagonal motif are of fundamental importance to understand the underlying science and for technological applications.