First-principles study of wurtziteBC2N

Abstract

The structural, electronic, and mechanical properties have been calculated by using first-principles pseudopotential density functional method for three possible configurations of wurtzite $\mathrm{B}{\mathrm{C}}_{2}\mathrm{N}$, which are deduced from four-atom wurtzite boron nitride unit cell. Our results show that the $\mathrm{B}{\mathrm{C}}_{2}\mathrm{N}\text{\ensuremath{-}}\mathrm{w}3$ with the maximum C-C and B-N bonds has the lowest total energy among all the reported $s{p}^{3}$-bonded $\mathrm{B}{\mathrm{C}}_{2}\mathrm{N}$ structures. Energetically, the wurtzite structure is more stable than the zinc-blende structure for the $s{p}^{3}$-bonded $\mathrm{B}{\mathrm{C}}_{2}\mathrm{N}$, which is different from $s{p}^{3}$-bonded carbon and boron nitride. The present $\mathrm{B}{\mathrm{C}}_{2}\mathrm{N}\text{\ensuremath{-}}\mathrm{w}3$ has the highest density, the largest bulk and shear moduli, the largest band gap, and the largest Vickers hardness among all the investigated $s{p}^{3}$-bonded $\mathrm{B}{\mathrm{C}}_{2}\mathrm{N}$ structures. The phase stability of $\mathrm{B}{\mathrm{C}}_{2}\mathrm{N}\text{\ensuremath{-}}\mathrm{w}3$ indicates that it should be experimentally synthesized more easily than the zinc-blende-structured $\mathrm{B}{\mathrm{C}}_{2}\mathrm{N}$.