Co/Si(111) interface formation at room temperature

Using the Auger line shape of Co atoms adsorbed on Si(111) at room temperature, we have been able to deduce detailed information on the development of the Co/Si interface which shows the initial formation of a boundary ${\mathrm{CoSi}}_2$-like phase. Simulation of these Auger lines within the Cini-Sawatzky theoretical scheme allows one to estimate the effective Coulomb interaction $U_{\mathrm{eff}}$ of the final two-hole state in the Auger process for bulk Co and cobalt silicides. Finally, in order to confirm these spectroscopic results, lattice-imaging micrographs directly suggest the presence of an interfacial ${\mathrm{CoSi}}_2$ layer.