I–V LEED study of Neodymium adsorption on W(110) at submonolayer coverage

Abstract

The adsorption of neodymium (Nd) atoms on W(110) surface was studied by means of the LEED, AES and work function change measurements. It was found out, that Nd atoms form a set of dilute chain structures at coverages below 1 ML similarly to previously investigated rare earth metals (REM) adsorbed on Mo(110). The absence of particular fractional diffraction proved that the atoms in dilute chain structures form a zigzag not only in the case of the Mo(110) substrate but also for adsorption of REM on W(110). As a result of the glide plane symmetry considerations a modified model was proposed with a different configuration of adatoms in the unit cell of the surface forming the zigzag. To support the new hypothesis an I–V LEED analysis was made for the (6 × 2) Nd/W(110) dilute chain system. Several theoretical structures were tested in dynamical scattering simulations, including a centered structure with inequivalent adsorption sites in consecutive chains and a zigzag chain previously discussed in the literature. Ultimately the I–V LEED experiment validated a new modified zigzag chain model.