Elastic and electronic properties of Imm2-and I(4)over-barm2-BCN

Based on density function theory with the ultrasoft pseudopotential scheme in the frame of the local density approximation and the generalized gradient approximation, we have systematically studied the structural stability, elastic properties, and mechanical properties of BCN compound with Imm2 and I (4) over bar m2 phases. It was found that Imm2 and I (4) over bar m2 phases are both mechanically stable. Imm2 phase is a direct semiconductor with bandgap of 2.54 eV, whereas I (4) over bar m2 phase is an indirect semiconductor with bandgap of 0.45 eV. The bulk modulus, shear modulus, Young's modulus, Poisson's ratio and Debye temperature have been calculated. For Imm2 (I (4) over bar m2) phase, the bulk modulus, shear modulus, Young's modulus and Debye temperature are 365 GPa (345 GPa), 394 GPa (358 GPa), 839 GPa (798 GPa) and 1925 K (1841 K). (C) 2014 Elsevier B.V. All rights reserved.