Electronic Structure, Phase Stability and Resistivity of Hybrid Hexagonal C$_x$(BN)$_{1-x}$ Two-dimensional Nanomaterial: A First-principles Study

TL;DR

This study employs first-principles calculations to explore the electronic structure, phase stability, and resistivity of hybrid hexagonal C$_x$(BN)$_{1-x}$ nanomaterials, revealing non-monotonic band-gap behavior and Dirac-like features at high carbon concentrations.

Contribution

It provides detailed electronic and stability analysis of C$_x$(BN) nanomaterials, including bandstructure, phase stability, and resistivity, based on first-principles methods, which was not previously comprehensively studied.

Findings

Band-gap decreases non-monotonically with carbon concentration

Dirac cone-like features emerge at high carbon content ($x \,\sim\, 0.8$)

Resistivity shows linear behavior in log scale against inverse temperature

Abstract

We use density functional theory based first-principles method to investigate the bandstructure and phase stability in the laterally grown hexagonal C$_x$(BN)$_{1-x}$, two-dimensional Graphene and $h$-BN hybrid nanomaterials, which were synthesized by experimental groups recently (Liu $et al$, Nature Nanotech, 8, 119 (2013)). Our detail electronic structure calculations on such materials, with both armchair and zigzag interfaces between the Graphene and $ h$-BN domains, indicate that the band-gap decreases non-monotonically with the concentration of Carbon. The calculated bandstructure shows the onset of Dirac cone like features near the band-gap at high Carbon concentration ($x \sim 0.8$). From the calculated energy of formation, the phase stability of C$_x$(BN)$_{1-x}$ was studied using a regular solution model and the system was found to be in the ordered phase below a few thousand Kelvin. Furthermore, using the Boltzmann transport theory we calculate the electrical resistivity from the bandstrcture of C$_x$(BN)$_{1-x}$ at different temperature ($T$), which shows a linear behaviour when plotted in the logarithmic scale against $T^{-1}$, as observed experimentally