Ab initio prediction of Boron compounds arising from Borozene: Structural and electronic properties

TL;DR

This study uses first principles calculations to analyze the structure, electronic properties, and transport behavior of boron clusters derived from borozene, revealing their semiconducting nature and the impact of impurities.

Contribution

It introduces novel boron cluster structures derived from borozene and provides detailed analysis of their stability, electronic properties, and transport characteristics using first-principles methods.

Findings

Pure boron clusters are planar with (3c-2e) bonds and aromaticity.

Impurities reduce stability and disrupt planarity.

Clusters exhibit semiconducting behavior with low bias conductance.

Abstract

Structure and electronic properties of two unusual boron clusters obtained by fusion of borozene rings has been studied by means of first principles calculations, based on the generalized-gradient approximation of the density functional theory, and the semiempirical tight-binding method was used for the transport calculations. The role of disorder has also been considered with single vacancies and substitutional atoms. Results show that the pure boron clusters are topologically planar and characterized by (3c-2e) bonds, which can explain, together with the aromaticity (estimated by means of NICS), the remarkable cohesive energy values obtained. Such feature makes these systems competitive with the most stable boron clusters to date. On the contrary, the introduction of impurities compromises stability and planarity in both cases. The energy gap values indicate that these clusters possess a semiconducting character, while when the larger system is considered, zero-values of the density of states are found exclusively within the HOMO-LUMO gap. Electron transport calculations within the Landauer formalism confirm these indications, showing semiconductor-like low bias differential conductance for these stuctures. Differences and similarities with Carbon clusters are highlighted in the discussion.