2D $B_xC_{1-x}$ Layers as Predicted by the Cluster-Expansion Approach

In this work, the cluster-expansion method combined with extensive first-principles calculations is used for predicting the most stable 2D $B_xC_{1-x}$ (x ≤0.5) layers. For concentrations of B up to ≈ 38%, the honeycomb structure of the boron-carbon compound is preserved, whereas for larger concentrations, the boron atoms tend to form 2D clusters and/or ribbons that are fragments of a triangular boron sheet. Our studies indicate that the incorporation of boron into graphene is energetically unfavorable even for low concentrations of B, however, the graphene-like structure of the $B_xC_{1-x}$ layer may be stabilized by a metallic substrate.