College of Information and Control Engineering, Xi'an University of Architecture and Technology, Xi'an, Shaanxi Province 710055, People's Republic of China.
College of Science, Xi'an University of Architecture and Technology, Xi'an, Shaanxi Province 710055, People's Republic of China.
IUCrJ. 2023 Jul 1;10(Pt 4):464-474. doi: 10.1107/S2052252523004207.
A total of 87 new monoclinic silicon allotropes are systematically scanned by a random strategy combined with group and graph theory and high-throughput calculations. The new allotropes include 13 with a direct or quasi-direct band gap and 12 with metallic characteristics, and the rest are indirect band gap semiconductors. More than 30 of these novel monoclinic Si allotropes show bulk moduli greater than or equal to 80 GPa, and three of them show even greater bulk moduli than diamond Si. Only two of the new Si allotropes show a greater shear modulus than diamond Si. The crystal structures, stability (elastic constants, phonon spectra), mechanical properties, electronic properties, effective carrier masses and optical properties of all 87 Si monoclinic allotropes are studied in detail. The electron effective masses m of five of the new allotropes are smaller than that of diamond Si. All of these novel monoclinic Si allotropes show strong absorption in the visible spectral region. Taken together with their electronic band gap structures, this makes them promising materials for photovoltaic applications. These investigations greatly enrich the current knowledge of the structure and electronic properties of silicon allotropes.
通过随机策略结合群论和图论以及高通量计算，系统地扫描了总共 87 种新的单斜硅同素异形体。这些新的同素异形体包括 13 种具有直接或准直接带隙和 12 种具有金属特性的同素异形体，其余的都是间接带隙半导体。这些新型单斜硅同素异形体中，超过 30 种的体弹模量大于或等于 80GPa，其中三种的体弹模量甚至大于金刚石硅。只有两种新的硅同素异形体的剪切模量大于金刚石硅。详细研究了 87 种单斜硅同素异形体的晶体结构、稳定性（弹性常数、声子谱）、力学性能、电子性能、有效载流子质量和光学性能。五种新同素异形体的电子有效质量 m 小于金刚石硅。所有这些新型单斜硅同素异形体在可见光光谱区域都表现出强烈的吸收。再加上它们的能带隙结构，这使它们成为有前途的光伏应用材料。这些研究极大地丰富了当前硅同素异形体结构和电子性质的知识。
