First-Principles Calculations: Structural, Anisotropic, and Electronic Properties of BC14 Carbon Under Pressure

This work investigates the structural, mechanical, and electrical properties of the superhard semiconductor carbon BC14 under pressure, based on density functional theory (DFT). BC14 formed by sp 3 hybridization still maintains good mechanical stability and dynamic stability under 100 GPa pressure. The relative enthalpy of BC14 increases gradually at a slower rate and is always much lower than that of BC12, C 96 , T-carbon, TY-carbon, and Y-carbon. The elastic constant, elastic modulus, and ratio of bulk modulus ( B ) to shear modulus ( G ) increase with pressure, while the hardness exhibits a decreasing tendency. BC14 is anisotropic in elastic mechanics, and its Young’s modulus ( E ) is isotropic in the (111) direction. Increasing pressure leads to the anisotropy of elastic modulus becoming stronger. From 0 GPa to 100 GPa, the band gap increases from 5.56 eV to 6.07 eV, and inherits indirect characteristics. No obvious effect of pressure is observed with regard to the number of diffraction peaks in the XRD pattern, but the diffraction peaks are slightly shifted.