Possible complete miscibility of (BN)x(C2)1-x alloys -: art. no. 092104

The stabilities of (BN)(x)(C-2)(1-x) alloys and related superlattices are investigated by ab initio pseudopotential calculations. We find that the (BN)(1)/(C-2)(1) superlattices in (111) orientations have the lowest formation energy among many short-range ordered BNC2 structures because of the smallest number of B-C and C-N bonds. Based on the calculated formation energies at several compositions and for various ordered structures and assuming thermodynamic equilibrium, the solid solution phase diagram of (BN)(x)(C-2)(1-x) alloys is constructed. We find that the complete miscibility of (BN)(x)(C-2)(1-x) alloys is possible, which is in contrast with previous theoretical predictions, but in agreement with experimental reports.