Li Yafei, Liao Yunlong, Schleyer Paul von Ragué, Chen Zhongfang
Department of Chemistry, Institute for Functional Nanomaterials, University of Puerto Rico, Rio Piedras Campus, San Juan, PR 00931, USA.
Nanoscale. 2014 Sep 21;6(18):10784-91. doi: 10.1039/c4nr01972e. Epub 2014 Aug 7.
Inspired by our theoretical finding that C₂Al₆(2-) has a planar D₂h minimum with two planar tetracoordinate carbons (ptCs), we computationally designed a new two-dimensional (2D) inorganic material, an Al₂C monolayer. All carbons in this monolayer are ptC's, stabilized inductively by binding to four electropositive Al atoms in the same plane. The Al₂C monolayer is semiconducting with an indirect minimum band gap and a slightly larger direct band gap. Good persistence of the Al₂C monolayer is indicated by its moderate cohesive energy, the absence of imaginary modes in its phonon spectrum, and the high melting point predicted by molecular dynamics (MD) simulations. Moreover, a particle-swarm optimization (PSO) global minimum search found the Al₂C monolayer to be the lowest-energy 2D structure compared to other Al₂C alternatives. Dividing the Al₂C monolayer results in one-dimensional (1D) Al₂C nanoribbons, which are computed to have quite rich characteristics such as direct or indirect band gaps with various values, depending on the direction of the division and the resulting edge configuration.
受我们的理论发现启发，即C₂Al₆(2-)具有一个平面D₂h最低点，其中含有两个平面四配位碳（ptC），我们通过计算设计了一种新型二维（2D）无机材料——Al₂C单层。该单层中的所有碳均为ptC，通过与同一平面内的四个电正性Al原子结合而被诱导稳定。Al₂C单层是半导体，具有间接最小带隙和稍大的直接带隙。Al₂C单层具有适度的内聚能、声子谱中不存在虚模以及分子动力学（MD）模拟预测的高熔点，表明其具有良好的稳定性。此外，粒子群优化（PSO）全局最小搜索发现，与其他Al₂C替代物相比，Al₂C单层是能量最低的二维结构。将Al₂C单层分割会得到一维（1D）Al₂C纳米带，根据分割方向和所得边缘构型，计算得出其具有相当丰富的特性，例如具有不同值的直接或间接带隙。
