Surface ferromagnetism in non-magnetic and dilute magnetic oxides

Abstract

We explore hole-doping as an efficient route to develop magnetism in simple nonmagnetic oxides. Based on ab-initio calculations of the prototypical material ZnO, we show that local spin polarization can be obtained even in the absence of magnetic dopants both in the bulk or at surfaces. However, the onset of long-range magnetic order additionally requires extended states, that can be achieved in surfaces without distorting the host lattice. We propose different possibilities which either profit the spontaneous polarization of Oxygen p states under defective charge conditions, or require the presence of adsorbates.