Modeling STM tips by single absorbed atoms on W(100) films: 3d and 4d transition-metal atoms - art. no. 125108

In order to provide comprehensive data on the electronic structure of reali stic STM tips we have studied tungsten (100) films with adsorbed single 3d and 4d transition-metal atoms by ab initio molecular-dynamics and full pote ntial methods. Molecular dynamics using ultrasoft pseudopotentials has been used to determine the relaxation of adsorbate and surface layers. Subseque ntly the electronic structure of the relaxed model tip has been calculated with an all-electron full potential method. The results suggest that the ch emical nature of the tip apex to a high degree determines achievable corrug ations and that results for current and corrugation values in a perturbatio n approach might be considerably improved by including the electronic struc ture of the tip.