Atsalakis Apostolos, Tsetseris Leonidas
Department of Physics, National Technical University of Athens, GR-15780 Athens, Greece.
J Phys Condens Matter. 2014 Jul 16;26(28):285301. doi: 10.1088/0953-8984/26/28/285301. Epub 2014 Jun 19.
Interest in two-dimensional (2D) forms of Si and Ge has surged recently, with a focus on silicene and germanene, the Si- and Ge-based analogues of graphene, as well as their derivatives. Siloxene and germoxene are 2D materials made of honeycomb Si and Ge backbone sheets that are decorated with H atoms and OH groups. Here we use first-principles calculations to probe the properties of their various conformations. We show that the most stable siloxene (and germoxene) polymorph is the so-called washboard structure, and not the chair geometry assumed in previous studies. The stability of the washboard configuration relates to the formation of a network of hydrogen bonds between its hydroxyl groups. We also find with hybrid functional calculations that siloxene and germoxene are wide band-gap semiconductors with gap values of 3.20 eV and 2.64 eV, respectively. Finally, we show that H and OH vacancies introduce spin polarization in these 2D materials and have a tendency to pair up in stable di-vacancies.
最近，对二维（2D）形式的硅和锗的兴趣激增，重点是硅烯和锗烯，它们是石墨烯的硅基和锗基类似物及其衍生物。硅氧烯和锗氧烯是由蜂窝状硅和锗主链片制成的二维材料，这些主链片上装饰有氢原子和羟基。在这里，我们使用第一性原理计算来探究它们各种构象的性质。我们表明，最稳定的硅氧烯（和锗氧烯）多晶型是所谓的搓衣板结构，而不是先前研究中假设的椅式几何结构。搓衣板构型的稳定性与其羟基之间形成的氢键网络有关。我们还通过杂化泛函计算发现，硅氧烯和锗氧烯是宽带隙半导体，带隙值分别为3.20电子伏特和2.64电子伏特。最后，我们表明氢和羟基空位在这些二维材料中引入了自旋极化，并且倾向于在稳定的双空位中配对。
