Dresden 2011 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 37: Magnetic Semiconductors II
MA 37.6: Vortrag
Mittwoch, 16. März 2011, 16:00–16:15, HSZ 401
Magnetic Properties of Polar ZnO Surfaces from Ab-Initio Calculations — •Guntram Fischer1, Arthur Ernst2, Waheed Adeagbo1, Nadia Sanchez3, Zdzislawa Szotek4, Walter Temmerman4, Wolfram Hergert1, and Carmen Muñoz3 — 1University of Halle, Halle, Germany — 2Max-Planck-Institute for Microstructure Physics, Halle, Germany — 3Instituto de Ciencia de Materiales de Madrid, Madrid, Spain — 4Daresbury Laboratory, Warrington, United Kingdom
We have investigated a magnetic moment formation of three oxygen-terminated polar ZnO surfaces. Specifically, these are the (000-1) surface, the (0001) surface with an oxygen atom on top of the Zn atom [(0001)-t], and the (0001) surface with an oxygen atom in a threefold hollow site [(0001)-h].
In this study we have used a multi-code approach allowing us to relax the surface structure and calculate the Heisenberg exchange parameters via a magnetic force theorem. Also, the influence of applying self-interaction corrections (SIC) to the oxygen p orbitals has been investigated.
Our calculations show that all three surfaces are magnetic. In addition, we find that applying SIC is necessary to correctly describe the top oxygen atom of the (0001)-h and (0001)-t surfaces, for both of which we find Curie temperatures to be larger than room temperature. The latter have been derived from Monte Carlo simulations based on the calculated exchange parameters.