论文标题
新型四方C8（钻石）和SI8同素体和二进制SI4C4相的碳硅系统中的第一原理研究
First principles investigations in the carbon silicon system of novel tetragonal C8 (diamond) and Si8 allotropes and binary Si4C4 phase
论文作者
论文摘要
C8，SI8和碳化硅SI4C4的新型扩展网络是基于晶体化学基本原理和优化结构提出的，以在密度功能理论（DFT）内进行基态能量和衍生的物理特性。两种碳和硅同素异形物以及碳化硅属于原始的四方空间群P-4M2编号115。C8c8同种异体结构由角落共享C4和Si4 Tetrahedra制成，由电荷密度投影显示，SP3像碳杂交一样。从仔细的对称分析中，对C8的对称分析表明，它是立方钻石的另一种表示，空间群F-D3M数字227。C8被确定为具有类似Vickers硬度的超硬。对C8的兴趣是作为研究Si8和Si-C二元的模板。发现Si8同素质量具有HV = 13 GPA立方SI，并且SI4C4鉴定出HV = 33 GPA接近实验性SIC。这三个新阶段均为机械（弹性常数）和动态（声音）稳定，其电子带结构的特征是使C8（Diamond）具有约5 eV的较大带隙，并且半导体SI8和SI4C4具有约1 eV的带隙。
Novel extended networks of C8, Si8 and silicon carbide Si4C4 are proposed based on crystal chemistry rationale and optimized structures to ground state energies and derived physical properties within the density functional theory (DFT). The two carbon and silicon allotropes and the silicon carbide belong to primitive tetragonal space group P-4m2 Number 115. C8 allotrope structure made of corner sharing C4 and Si4 tetrahedra is illustrated by charge density projections exhibiting sp3 like carbon hybridization. From careful symmetry analysis, Symmetry analysis of C8 indicated that it is another representation of cubic diamond, space group F-d3m Number 227. C8 is identified as ultra-hard with a similar magnitude of Vickers hardness. The interest in C8 is to serve as template to study Si8 and Si-C binary. Si8 allotrope is found soft with HV =13 GPa alike cubic Si, and Si4C4 is identified with HV =33 GPa close to experimental SiC. All three new phases are mechanically (elastic constants) and dynamically (phonons) stable, and their electronic band structures are characteristic of insulating C8 (diamond) with large band gaps of about 5 eV, and semi-conducting Si8 and Si4C4 with band gaps of about 1 eV.
