(n × n) Surface structures formed commonly on Cu(001), Ag(001) and Ni(001) by alkali-metal adsorption

We have studied structures formed on Ag(001) by Na adsorption at 300 K and on Ni(001) by Li deposition at 370 K by means of low energy electron diffraction (LEED). Structure sequences (2 × 1) → (3 × 3) → (4 × 4) → (4 × 2) → (2 × 1) and c(2 × 2) → (4 × 4) → (5 × 5) are found with increasing coverages for Na/Ag(001) and Li/Ni(001), respectively. The (3 × 3) for Na/Ag(001) is determined by tensor LEED analysis to be identical to the previously determined (3 × 3) structure formed for Li/Cu(001). We suggest that the (4 × 4) structures for Na/Ag(001) and Li/Ni(001) are also identical to the previously determined (4 × 4) for Li/Cu(001), and that the (5 × 5) for Li/Ni(001) is analogous to the (3 × 3) and (4 × 4) structures.