On the Electronic Structure of a Recently Synthesized Graphene-like BCN Monolayer from bis-BN Cyclohexane: A DFT Study

TL;DR

This DFT study explores the electronic and structural properties of a novel graphene-like BCN monolayer with vacancies, revealing defect-induced states, charge localization, and magnetic properties, aligning well with experimental bandgap measurements.

Contribution

The paper provides a detailed theoretical analysis of vacancy effects on a recently synthesized BCN monolayer, highlighting defect-induced electronic and magnetic phenomena.

Findings

Vacancies cause lattice distortion and bond reconstruction.

Midgap states appear due to vacancies, affecting electronic properties.

Boron vacancies induce spontaneous magnetization with a magnetic moment.

Abstract

Since the rising of graphene, boron nitride monolayers have been deeply studied due to their structural similarity with the former. A hexagonal graphene-like boron-carbon-nitrogen (h-BCN) monolayer was synthesized recently using bis-BN cyclohexane (B2N2C2H12) as a precursor molecule. Herein, we investigated the electronic and structural properties of this novel BCN material, in the presence of single-atom (boron, carbon, or nitrogen) vacancies, by employing density functional theory calculations. The stability of these vacancy-endowed structures is verified from cohesion energy calculations. Results showed that a carbon atom vacancy strongly distorts the lattice leading to breaking on its planarity and bond reconstructions. The single-atom vacancies induce the appearance of flat midgap states. A significant degree of charge localization takes place in the vicinity of these defects. It was observed a spontaneous magnetization only for the boron-vacancy case, with a magnetic dipole moment about 0.87 mu_B. Our calculations predicted a direct electronic bandgap value of about 1.14 eV, which is in good agreement with the experimental one. Importantly, this bandgap value is intermediate between gapless graphene and insulating h-BN.