Structural and statistical analysis of Yb/Si(1 1 1) and Eu/Si(1 1 1) reconstructions

We have performed the structural and statistical analysis of Yb/Si(1 1 1) and Eu/Si(1 1 1) surfaces in the submonolayer regime utilizing low-energy electron diffraction and scanning tunneling microscopy (STM). The almost identical series of one-dimensional chain structures (e.g., 3 × 2/3 × 1, 5 × 1, 7 × 1, 9 × 1, and 2 × 1 phases) are found in order of increasing metal coverage for both adsorbed systems, however, only the Eu/Si system reveals the ‘√3’-like reconstruction before the 2 × 1 endpoint phase. The atomic models of chain structures are proposed and discussed. In particular, our results suggest the odd-order n×1 (n=5,7,9,…) intermediate reconstructions to incorporate the Seiwatz chains and honeycomb chains with the proportion of m:1, where m=n−12−1. The statistical analysis of STM images is carried out to examine the correlation of atomic rows on Eu/Si and Yb/Si surfaces. It is found that Eu stabilizes more ordered row configuration compared to Yb, which can be explained in terms of indirect electronic interaction of atomic chains or/and different magnetic properties of adsorbed species.