Ordering effects in 2D hexagonal systems of binary and ternary BCN alloys

Abstract

We present theoretical study of ordering phenomena in binary $C_{1-x}B_{x}$, $C_{1-x}N_{x}$ and ternary $B_{x}C_{1-x-y}N_{y}$ alloys forming two-dimensional, graphene-like systems. For calculating energy of big systems (20 000 atoms in the supercell with periodic boundary conditions assumed) empirical Tersoff potential was employed. In order to find equilibrium distribution of different species corresponding to minima of the energy, we use Monte Carlo approach in Metropolis regime. We take into consideration wide range of concentrations (1-50%) and temperatures (70-1500 K), to provide more complete picture. For quantitative description of order, we determine Warren-Cowley Short Range Order (SRO) parameters for the first coordination shell. This procedure allows us to determine energetically favorable compositions of all alloys, and characterize resulting types of order for both binary and ternary systems.