摘要
Structural, electronic properties and mechanical anisotropy of Amm2-carbon are investigated utilizing tlrst-principles calculations by Oambridge Serial Total Energy Package （CASTEP） code. The work is performed with the generalized gradient approximation in the form of Perdew Burke-Ernzerhof （PBE）, PBEsol, Wu and Cohen （WC） and local density approximation in the form of Ceperley and Alder data as parameterized by Perdew and Zunger （CA-PZ）. The mechanical anisotropy eMculations show that Amm2-carbon exhibit large anisotropy in elastic moduli, such as Poisson＇s ratio, shear modulus and Young＇s modulus, and other anisotropy factors, such as the shear anisotropic factor and the universal anisotropic index AU. It is interestingly that the anisotropy in shear modulus and Young＇s modulus, universal anisotropic index and the shear anisotropie factor all increases with increasing pressure, but the anisotropy in Poisson＇s ratio decreases. The band structure calculations reveal that Amm2-carbon is a direct-band-gap semiconductor at ambient pressure, but with the pressure increasing, it becomes an indirect-band-gap semiconductor.
基金
Supported by the National Natural Science Foundation of China under Grant No.61564005
