Merino P, Rosławska A, Grewal A, Leon C C, Gonzalez C, Kuhnke K, Kern K
Max Planck Institute for Solid State Research, Heisenbergstraße 1, D70569 Stuttgart, Germany.
Instituto de Ciencia de Materiales de Madrid, CSIC, Sor Juana Inés de la Cruz 3, E28049 Madrid, Spain.
ACS Nano. 2020 Nov 24;14(11):15241-15247. doi: 10.1021/acsnano.0c05507. Epub 2020 Oct 29.
The hexagonal close packed surface of gold shows a 22 × "herringbone" surface reconstruction which makes it unique among the (111) surfaces of all metals. This long-range energetically favored dislocation pattern appears in response to the strong tensile stress that would be present on the unreconstructed surface. Adsorption of molecular and atomic species can be used to tune this surface stress and lift the herringbone reconstruction. Here we show that herringbone reconstruction can be controllably lifted in ultrahigh vacuum at cryogenic temperatures by precise hot electron injection in the presence of hydrogen molecules. We use the sharp tip of a scanning tunneling microscope (STM) for charge carrier injection and characterization of the resulting chain nanostructures. By comparing STM images, rotational spectromicroscopy and calculations, we show that formation of gold atomic chains is associated with release of gold atoms from the surface, lifting of the reconstruction, dissociation of H molecules, and formation of surface hydrides. Gold hydrides grow in a zipper-like mechanism forming chains along the [11̅0] directions of the Au(111) surface and can be manipulated by further electron injection. Finally, we demonstrate that Au(111) terraces can be transformed with nearly perfect terrace selectivity over distances of hundreds of nanometers.
金的六方密排表面呈现出一种22ד人字形”表面重构，这使其在所有金属的(111)表面中独一无二。这种远距离能量有利的位错模式是由于未重构表面上存在的强拉伸应力而出现的。分子和原子物种的吸附可用于调节这种表面应力并消除人字形重构。在此我们表明，在低温下的超高真空中，通过在氢分子存在下精确注入热电子，可以可控地消除人字形重构。我们使用扫描隧道显微镜(STM)的尖锐针尖进行电荷载流子注入并表征由此产生的链状纳米结构。通过比较STM图像、旋转光谱显微镜和计算结果，我们表明金原子链的形成与金原子从表面释放、重构的消除、H分子的解离以及表面氢化物的形成有关。氢化金以拉链状机制生长，沿着Au(111)表面的[11̅0]方向形成链，并且可以通过进一步的电子注入进行操控。最后，我们证明Au(111)平台可以在数百纳米的距离上以近乎完美的平台选择性进行转变。
