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

TL;DR

This study investigates the temperature-dependent electronic and magnetic surface states of EuS thin films, combining first-principles and model calculations to reveal how surface states and magnetic stability evolve with temperature and thickness.

Contribution

It introduces a combined first-principles and ferromagnetic Kondo-lattice model approach to analyze EuS films, providing detailed insights into surface states and magnetic properties at finite temperatures.

Findings

Thickness-dependent Curie temperature matches experimental data

Surface states exhibit spin splitting and decay exponentially with distance from surface

Surface electronic structure is strongly influenced by temperature and damping effects

Abstract

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.