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O: Fachverband Oberflächenphysik

O 4: Surface Magnetism: Atoms and Molecules

O 4.4: Talk

Monday, March 7, 2016, 11:15–11:30, S052

The fascinating versatility of wustite surfaces — •Silvia Gallego and Ivan D. Bernal-Villamil — Instituto de Ciencia de Materiales de Madrid, Madrid, Spain

Wustite (FeO) belongs to the magnetic transition metal monoxides series, a set of antiferromagnetic Mott insulators with a simple rock-salt structure. Among them, wustite is singular in its high content of Fe vacancies at ambient conditions, that introduce local polaronic charge distributions and alter the magnetization.

Mono- and bi-layer FeO has been grown and largely studied, but it reverts to Fe3O4 as the thickness increases, accompanied by a yet not solved 2x2 surface structure with unexpected magnetic features. Based on ab initio calculations, in this talk we will provide our solution for this 2x2 structure, explaining the evolution of FeO to Fe3O4, and the origin of the magnetism. Furthermore, we will show how surface processes are involved in the growth of unusually thick stoichiometric FeO films, that hold a 1x1 symmetry and robust bulk-like antiferromagnetic order.