Evolution of step and terrace structure on [1̄ 1̄ 2]- and [1 1 2̄]-miscut Si(1 1 1) surfaces upon formation of triple- and single-domain Yb-induced 3 × 2 reconstruction

Evolution of step and terrace structures on vicinal Si(1 1 1) surfaces miscut 4° in the [1̄ 1̄ 2] and [1 1 2̄] directions after the 3 × 2-Yb formation and subsequent annealing in the temperature range of 500–790 °C has been investigated by room temperature scanning tunneling microscopy and low-energy electron diffraction. On the [1̄ 1̄ 2]-miscut surface, steps favor the nucleation of Yb-induced 3 × 2 domains oriented along step edges and depress the other domain orientations after properly chosen annealing temperature. Simultaneously with the triple- to single-domain transition, the single- and triple-layer step structure observed for the Si(1 1 1)-7 × 7 and 3 × 2-Yb triple-domain surface is converted into the mixture of step heights where double-layer steps dominate. Contrary to the case of [1̄ 1̄ 2]-miscut surface, no 3 × 2-Yb triple- to single-domain transition is observed after annealing cycles on the [1 1 2̄]-miscut surface. However, the step bunch splitting and the more unified 3 × 2-Yb domains are revealed after annealing at 750 °C.