Cavendish Laboratory, University of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE, UK.
J Phys Condens Matter. 2011 Sep 7;23(35):355001. doi: 10.1088/0953-8984/23/35/355001. Epub 2011 Jul 21.
We use helium atom scattering to investigate the structures formed by Li adsorption onto Cu(001) in the 0-2 ML regime. Submonolayer growth at 180 K proceeds through a sequence of ordered overlayers, including a c(2 × 2) structure at 0.5 ML and a series of 'ladder' superlattices around 0.6 ML. Beyond 1 ML, incommensurate, three-dimensional Li islands develop. A quantum close-coupled scattering analysis is performed to study the empirical He-surface potential of the structurally heterogeneous ladder structures. Good agreement with the measured distribution of diffracted intensity is obtained by describing the He-ladder interaction potential as the summation of only six one-dimensional Fourier components. The fitted potential indicates a remarkably flat surface that is punctuated by substantial, striped protrusions in the electron density. The result is consistent with the formation of one-dimensional Li wires, indicating an inhomogeneous metallization process.
我们使用氦原子散射来研究 Li 在 0-2 ML 范围内吸附到 Cu(001)上形成的结构。在 180 K 下亚单层生长经历了一系列有序的覆盖层，包括在 0.5 ML 时的 c(2×2)结构和在大约 0.6 ML 时的一系列“阶梯”超晶格。超过 1 ML 后，非共格的三维 Li 岛发展起来。进行了量子紧束缚散射分析，以研究结构不均匀的阶梯结构的经验 He-表面势能。通过将 He-阶梯相互作用势能描述为仅六个一维傅里叶分量的和，得到了与测量的衍射强度分布很好的一致性。拟合的势能表明表面非常平坦，只是在电子密度中有很大的、条纹状的凸起。这一结果与一维 Li 线的形成一致，表明了不均匀的金属化过程。
