Bremen Center for Computational Materials Science, University of Bremen , Am Falturm 1, 28359 Bremen, Germany.
J Am Chem Soc. 2015 Feb 25;137(7):2757-62. doi: 10.1021/ja513209c. Epub 2015 Feb 13.
Two-dimensional (2D) materials with planar hypercoordinate motifs are extremely rare due to the difficulty in stabilizing the planar hypercoordinate configurations in extended systems. Furthermore, such exotic motifs are often unstable. We predict a novel Cu2Si 2D monolayer featuring planar hexacoordinate copper and planar hexacoordinate silicon. This is a global minimum in 2D space which displays reduced dimensionality and rule-breaking chemical bonding. This system has been studied with density functional theory, including molecular dynamics simulations and electronic structure calculations. Bond order analysis and partitioning reveals 4c-2e σ bonds that stabilize the two-dimensional structure. We find that the system is quite stable during short annealing simulations up to 900 K, and predict that it is a nonmagnetic metal. This work opens up a new branch of hypercoordinate two-dimensional materials for study.
二维（2D）材料具有平面高坐标基元的情况极为罕见，因为在扩展系统中稳定平面高坐标构型非常困难。此外，这种奇异的基元通常是不稳定的。我们预测了一种具有平面六配位铜和平面六配位硅的新型 Cu2Si 2D 单层。这是 2D 空间中的全局最小值，具有降低的维度和打破规则的化学成键。该系统已通过密度泛函理论进行了研究，包括分子动力学模拟和电子结构计算。键序分析和划分揭示了稳定二维结构的 4c-2eσ 键。我们发现，在高达 900 K 的短退火模拟中，该系统非常稳定，并预测它是一种无磁性金属。这项工作为研究开辟了一个新的高坐标二维材料分支。
