First-Principles Study on Atomistic Behaviors and Magnetism of Physisorpted Co and Fe Atoms on MgO(001) Surface

In this study, diffusion behaviors of Fe and Co adatoms on MgO (001) surface were investigated using the ab initio method. The energy barriers for diffusion behavior and magnetic properties, including the spin polarizations (SPs) and magnetic moments, were calculated for Fe/MgO (001) and Co/MgO (001) systems. According to the potential energy surface (PES) calculation for the Fe/MgO (001) system, the most stable adsorption site was the hollow site where the E_ad was 0.28 eV/(2 x 2). Mg and O atoms of the surface plane participated the bonding with the adsorbed Fe adatom representing the configuration of C2v symmetry. The bond lengths of Fe-Mg and Fe-0 were 2.31 A and 2.00 A, respectively.The magnetic moment of hollow site-adsorbed Fe atom was reduced to 2.99 mu _B from 3.50 mu _B of in vacuum state. The SP values calculated from the density of states for Fe atom/MgO (001) system were summarized with the comparison of Co/MgO (001) system.