Spin polarons in EuO layers: a quantum computational study

Abstract

Magnetic semiconductors are highly promising materials for spintronics. Among them europium(II) oxide makes a unique working host material due to a remarkable combination of magnetic and transport properties. Its electronic structure and various properties are often described in terms of spin polarons – local ferromagnetic clusters in the paramagnetic sea of Eu ions. This concept finds support in numerous experiments and theoretical studies but so far it has not emerged in quantum-chemical calculations of this material. Here we try to find evidence for the existence of these quasiparticles from local cluster calculations for different values of the total spin. Our calculations of EuO layers show that there are low-energy states consistent with quasi-two-dimensional spin polarons as part of their electronic structure. The size of these quasiparticles (radius R ≈ 0.5 nm and spin S ≈ 38) doesn't change with the size of the cluster and is in good accord with experimental results.