Ma Zhenyang, Liu Xuhong, Yu Xinhai, Shi Chunlei, Yan Fang
Tianjin Key Laboratory for Civil Aircraft Airworthiness and Maintenance, Civil Aviation University of China, Tianjin 300300, China.
Materials (Basel). 2017 May 31;10(6):599. doi: 10.3390/ma10060599.
The structural, mechanical, anisotropic, electronic and thermal properties of Si, SiGe, SiGe and Ge in 4₂/ phase are investigated in this work. The calculations have been performed with an ultra-soft pseudopotential by using the generalized gradient approximation and local density approximation in the framework of density functional theory. The achieved results for the lattice constants and band gaps of 4₂/-Si and 4₂/-Ge in this research have good accordance with other results. The calculated elastic constants and elastic moduli of the Si, SiGe, SiGe and Ge in 4₂/ phase are better than that of the Si, SiGe, SiGe and Ge in 4₂/ phase. The Si, SiGe, SiGe and Ge in 4₂/ phase exhibit varying degrees of mechanical anisotropic properties in Poisson's ratio, shear modulus, Young's modulus, and universal anisotropic index. The band structures of the Si, SiGe, SiGe and Ge in 4₂/ phase show that they are all indirect band gap semiconductors with band gap of 1.46 eV, 1.25 eV, 1.36 eV and 1.00 eV, respectively. In addition, we also found that the minimum thermal conductivity of the Si, SiGe, SiGe and Ge in 4₂/ phase exhibit different degrees of anisotropic properties in (001), (010), (100) and (01¯0) planes.
本工作研究了4₂/相中的Si、SiGe、SiGe和Ge的结构、力学、各向异性、电子和热学性质。计算是在密度泛函理论框架下，使用广义梯度近似和局域密度近似，并采用超软赝势进行的。本研究中得到的4₂/-Si和4₂/-Ge的晶格常数和带隙结果与其他结果吻合良好。计算得到的4₂/相中的Si、SiGe、SiGe和Ge的弹性常数和弹性模量优于4₂/相中的Si、SiGe、SiGe和Ge。4₂/相中的Si、SiGe、SiGe和Ge在泊松比、剪切模量、杨氏模量和通用各向异性指数方面表现出不同程度的力学各向异性性质。4₂/相中的Si、SiGe、SiGe和Ge的能带结构表明它们都是间接带隙半导体，带隙分别为1.46 eV、1.25 eV、1.36 eV和1.00 eV。此外，我们还发现4₂/相中的Si、SiGe、SiGe和Ge的最小热导率在(001)、(010)、(100)和(01¯0)平面上表现出不同程度的各向异性性质。
