Berlin 2012 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 58: Poster Session III (Solid/liquid interfaces; Metals; Semiconductors; Oxides and insulators)

O 58.50: Poster

Mittwoch, 28. März 2012, 18:15–21:45, Poster B

Density functional calculation of interface structure of Fe/ZnO — •Sougata Pal and Eckhard Pehlke — Institut für Theoretische Physik und Astrophysik, Universität Kiel, Germany

Interfaces between magnetic and piezoelectric materials bear the possibility of magnetoelectric coupling phenomena which occur at the interface, in addition to coupling via long range strain fields [1]. As a model system, we have started to investigate the adsorption of 1/4 – 1 ML Fe on both the unreconstructed and the (2×2) vacancy-reconstructed ZnO(0001) surfaces by means of density functional calculations. First, the lowest-energy structures have to be identified. Among the calculated adsorption sites, the fcc hollow position is energetically favorable. At sufficiently large oxygen chemical potential, the energy can be further lowered by substituting the top layer Zn-atoms with Fe atoms. In this case the Zn-atoms created by the Zn-Fe exchange are assumed to become oxidized and included into the ZnO bulk. It has turned out be energetically unfavorable, however, to exchange Zn-atoms in deeper layers with Fe-atoms. The interface between ZnO and the locally formed Fe-oxide is thus expected to be sharp. The findings are consistent with Fe-oxidation observed experimentally [2,3].

[1] J.M. Rondinelli, et al., Nature Nanotechnology 3, 46 (2008).

[2] A. Demund et al., Surf. Interface Anal. 40, 27 (2008).

[3] Guo-Dong Wang et al., Surf. Review and Lett. 15, 295 (2008).