Diffusion of N adatoms on the Fe(100) surface

The diffusion of individual N adatoms on Fe(100) has been studied using sca nning tunneling microscopy and ab initio density functional theory (DFT) ca lculations. The measured diffusion barrier for isolated N adatoms is E-d = (0.92 +/- 0.04) eV, with a prefactor of nu(0) = 4.3 x 10(12) s(-1), which i s in quantitative agreement with the DFT calculations. Thr; diffusion is st rongly coupled to lattice distortions. and. as a consequence, the presence of other N adatoms introduces an anisotropy in the diffusion. Based on expe rimentally determined values of the diffusion barriers and adsorbate-adsorb ate: interactions, the potential energy surface experienced by a N adatom i s determined.