School of Physics and Optoelectronic Engineering, Xidian University, Xi'an 710071, P. R. China.
Phys Chem Chem Phys. 2019 Sep 18;21(36):19963-19968. doi: 10.1039/c9cp03128f.
Six new silicon phases with direct band gaps were found through silicon atomic substitution of carbon in the known carbon structures via high-throughput calculations. The six newly discovered Si phases are in the space groups of Im3[combining macron]m, C2/c, I4/mcm, I4/mmm, P21/m, and P4/mbm, respectively. Their crystal structures, stabilities, mechanical properties, elastic anisotropy, and electronic and optical properties were systematically studied using first-principles density functional theory calculations. All the new phases were proved to be thermodynamically and mechanically stable at ambient pressure. The direct band gap values in the range of 0.658-1.470 eV and the excellent optoelectronic properties of these six Si allotropes suggest that they are promising photovoltaic materials compared to diamond silicon.
通过高通量计算，在已知的碳结构中用硅原子取代碳，发现了 6 种具有直接带隙的新硅相。这 6 种新发现的 Si 相分别属于 Im3[combining macron]m、C2/c、I4/mcm、I4/mmm、P21/m 和 P4/mbm 空间群。使用第一性原理密度泛函理论计算，系统地研究了它们的晶体结构、稳定性、力学性能、弹性各向异性以及电子和光学性质。所有新相在常压下均被证明是热力学和力学稳定的。这些 6 种 Si 同素异形体的直接带隙值在 0.658-1.470eV 范围内，具有优异的光电性能，表明它们是有前途的光伏材料，优于金刚石硅。
