Instituto de Ciencia de Materiales de Madrid, ICMM-CSIC, Cantoblanco, 28049 Madrid, Spain.
Aix Marseille Université, CNRS, PIIM UMR 7345, 13397 Marseille, France.
Nat Commun. 2016 Oct 6;7:13076. doi: 10.1038/ncomms13076.
Carbon and silicon pentagonal low-dimensional structures attract a great interest as they may lead to new exotic phenomena such as topologically protected phases or increased spin-orbit effects. However, no pure pentagonal phase has yet been realized for any of them. Here we unveil through extensive density functional theory calculations and scanning tunnelling microscope simulations, confronted to key experimental facts, the hidden pentagonal nature of single- and double-strand chiral Si nano-ribbons perfectly aligned on Ag(110) surfaces whose structure has remained elusive for over a decade. Our study reveals an unprecedented one-dimensional Si atomic arrangement solely comprising almost perfect alternating pentagons residing in the missing row troughs of the reconstructed surface. We additionally characterize the precursor structure of the nano-ribbons, which consists of a Si cluster (nano-dot) occupying a silver di-vacancy in a quasi-hexagonal configuration. The system thus materializes a paradigmatic shift from a silicene-like packing to a pentagonal one.
碳和硅的五边形低维结构引起了极大的兴趣，因为它们可能导致新的奇异现象，如拓扑保护相或增强的自旋轨道效应。然而，到目前为止，它们还没有任何一种纯五边形相被实现。在这里，我们通过广泛的密度泛函理论计算和扫描隧道显微镜模拟，结合关键的实验事实，揭示了单链和双链手性 Si 纳米带在 Ag(110)表面上的隐藏的五边形性质，这些纳米带的结构在过去十年中一直难以捉摸。我们的研究揭示了一种前所未有的一维 Si 原子排列，仅由几乎完美的交替五边形组成，这些五边形位于重构表面的缺失行槽中。我们还对纳米带的前体结构进行了表征，该结构由一个 Si 团簇（纳米点）以近乎六边形的准构型占据银的双空位组成。因此，该系统实现了从类硅烯堆积到五边形堆积的典范转变。
