We study the stability and electronic structure of previously unexplored two-dimensional (2D) ternary compounds ${\mathrm{BNP}}_2$ and ${\mathrm{C}}_2\mathrm{SiS}$. Using ab initio density functional theory, we have identified four stable allotropes of each ternary compound and confirmed their stability by calculated phonon spectra and molecular dynamics simulations. Whereas all ${\mathrm{BNP}}_2$ allotropes are semiconducting, we find ${\mathrm{C}}_2\mathrm{SiS}$, depending on the allotrope, to be semiconducting or semimetallic. The fundamental band gaps of the semiconducting allotropes we study range from $1.4\mathrm{eV}$ to $2.2\mathrm{eV}$ at the HSE06 level and display carrier mobilities as high as $1.5\times {10}^5{\mathrm{cm}}^2{\mathrm{V}}^{-1}{\mathrm{s}}^{-1}$. Such high mobilities are quite uncommon in semiconductors with so wide band gaps. Structural ridges in the geometry of all allotropes cause a high anisotropy in their mechanical and transport properties, promising a wide range of applications in electronics and optoelectronics.

中文翻译：

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具有高各向异性载流子迁移率的低对称二维BNP2和C2SiS结构

我们研究了以前未开发的二维（2D）三元化合物的稳定性和电子结构 ${\mathrm{法国巴黎银行}}_2$ 和 ${\mathrm{C}}_2\mathrm{矽统}$。使用从头算密度函数理论，我们确定了每种三元化合物的四个稳定同素异形体，并通过计算的声子谱和分子动力学模拟证实了它们的稳定性。而所有${\mathrm{法国巴黎银行}}_2$ 同素异形体是半导体的，我们发现 ${\mathrm{C}}_2\mathrm{矽统}$取决于同素异形体，是半导体或半金属。我们研究的半导体同素异形体的基本带隙范围为$1.4\mathrm{电子伏特}$ 至 $2.2\mathrm{电子伏特}$ 在HSE06级别上显示的运输能力高达 $1.5\times {10}^5{\mathrm{厘米}}^2{\mathrm{V}}^{-\mathrm{1个}}{\mathrm{s}}^{-\mathrm{1个}}$。在具有如此高的带隙的半导体中，如此高的迁移率并不常见。所有同素异形体的几何结构中的脊状结构均会导致其机械和传输性能出现高度各向异性，从而有望在电子和光电子领域得到广泛的应用。