Cobalt layers crystallized on the WC(100) surface: Spin-polarized ab initio study

► Quantum-mechanics calculations show that epitaxial layers of cobalt with atoms positioned above carbon atoms are preferable energetically. The second Co monolayer repeats the fcc geometry, however the distance between the first and second Co layers is less than the distance between planes in the WC and Co cubic crystals. The binding energy grows while the separation energy decreases, when going from 1 ML to 2 ML of cobalt covering. The density of states for the WC/Co system looks like the superposition of DOSes for bulk fcc-WC and Co layers. All Co layers are ferromagnetic ones, however, the magnetization does not influence essentially on their energies and geometries.