Nitrogen-induced reconstructions on the Cr(001) surface*

Cr is an essential material for various spintronic devices due to its magnetic properties. Nevertheless, it is necessary to selectively introduce a contaminant –like Nitrogen– during its synthesis to stabilize its highly-reactive surface. The main drawback is that N changes the electronic and magnetic properties; so, describing the adsorption and properties of adsorbed N is necessary. We described different reconstructions models of N on Cr(001) using DFT calculations andSTM data. With a theoretical thermodynamic analysis we identified the stable models for different growth conditions. From the four stable models, two were already described experimentally, while we confirmed the other two with a comparison of theoretical STM images and STM experiments. Both are in a c(2x2) configuration and the first one has N adsorbed on the hollow sites, while the second has N substituting surface Cr. The electronic and magnetic properties of both models confirmed that they preserve the main characteristics of the clean Cr surface.