Fan Qingyang, Chai Changchun, Wei Qun, Yang Yintang
Key Laboratory of Ministry of Education for Wide Band-Gap Semiconductor Materials and Devices, School of Microelectronics, Xidian University, Xi'an 710071, China.
School of Physics and Optoelectronic Engineering, Xidian University, Xi'an 710071, China.
Materials (Basel). 2016 May 30;9(6):427. doi: 10.3390/ma9060427.
We systematically studied the physical properties of a novel superhard (-C₃N₄) and a novel hard (-C₃N₄) C₃N₄ allotrope. Detailed theoretical studies of the structural properties, elastic properties, density of states, and mechanical properties of these two C₃N₄ phases were carried out using first-principles calculations. The calculated elastic constants and the hardness revealed that -C₃N₄ is ultra-incompressible and superhard, with a high bulk modulus of 375 GPa and a high hardness of 80 GPa. -C₃N₄ and -C₃N₄ both exhibit large anisotropy with respect to Poisson's ratio, shear modulus, and Young's modulus. Moreover, -C₃N₄ is a quasi-direct-bandgap semiconductor, with a band gap of 4.522 eV, and -C₃N₄ is also a quasi-direct-band-gap semiconductor, with a band gap of 4.210 eV, with the HSE06 functional.
我们系统地研究了一种新型超硬（-C₃N₄）和一种新型硬质（-C₃N₄）C₃N₄同素异形体的物理性质。利用第一性原理计算对这两种C₃N₄相的结构性质、弹性性质、态密度和力学性质进行了详细的理论研究。计算得到的弹性常数和硬度表明，-C₃N₄具有超不可压缩性和超硬性，其体模量高达375 GPa，硬度高达80 GPa。-C₃N₄和 -C₃N₄在泊松比、剪切模量和杨氏模量方面均表现出较大的各向异性。此外，-C₃N₄是一种准直接带隙半导体，带隙为4.522 eV，-C₃N₄在HSE06泛函下也是一种准直接带隙半导体，带隙为4.210 eV。
