The inter-adsorbate interaction mediated by Shockley-type surface state electrons and dipole moment:

• 作 者: Shuyuan Zhang Hong Zhang Yoshiyuki Miyamoto
• 机 构: Beijing National Laboratory for Condensed-Matter Physics and Institute of Physics, Chinese Academy o
• 出 处: 第十三届国际凝聚态理论与计算材料学会议(The 13th International Conference on Con
• 发表日期: 2014年8期

　　This investigation is conducted to reveal three main factors which can modulate the surface state mediated interaction: films thickness, adsorbate coverage and adatoms types.Through first-principles investigation, we display the films thickness influence on Shockley-type surface states which emerges on silver thin films along Ag(111) orientation with increasing thicknesses from 6 to 21 layers.As the thickness increasing, the binding energy, Fermi wave vector and bonding-antibonding are decreasing.Based on the influence of film thickness, we look at the surface state band for various adatoms (Cs and Ba) adsorbed on 6, 12, 18 layers strained Ag(111) films with different coverage, and discuss the long range interaction mediated by surface state electrons.In these surface systems, adsorbate assembly is controlled by two interactions.One is surface-state mediated interaction (attractive) and another one is dipole-dipole interaction (repulsive).We calculate the sum of the two interactions as a function of adatoms distance (d), and acquire the interatomic distance (dm) located at the first energy minimum to describe surface geometry structures.We observe the binding energy and the Fermi wave vector increasing with coverage added, and thicker films response drastically at high coverage (1/3 ML).The adsorbate separation displays that higher coverage leading to smaller separation.This tendency is also reported in Ref.and discussed widely.