Ferromagnetic EuS films: Magnetic stability, electronic structure and magnetic surface states

We present the temperature and layer dependent electronic structure of a 20-layer EuS(100)-film using a combination of first-principles and model calculation, the latter based on the ferromagnetic Kondo-lattice. The calculated thickness-dependent Curie temperature agrees very well with experimental data. The projected 5d-bandstructure is at finite temperatures strongly influenced by damping effects due to spin exchange processes. Spin-split unoccupied 5d-surfaces states are found with a Stoner-like collapsing for increasing temperature towards the Curie point and with an exponential decay of spectral weight with increasing distance from the surface.