Berlin 2008 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 48: ZnO: Preparation and characterization II
HL 48.4: Vortrag
Donnerstag, 28. Februar 2008, 10:15–10:30, ER 164
ZnO:Mnx valence configuration from the perspective of density functional theory — •Marc Andy Gluba and N. H. Nickel — Hahn-Meitner-Institut Berlin GmbH, Abt. Silizium Photovoltaik (SE1), Kekuléstraße 5, D-12489 Berlin, Germany
Zinc oxide (ZnO) doped with transition metal (TM) ions has attracted considerable interest because of its potential application as a base-material for spintronic devices. According to theoretical predictions by Dietl et al. manganese doped into ZnO should preserve its ferromagnetic order up to room temperature[1]. However, the experimental realization of dilute ferromagnetic ZnO is still challenging.
It is widely accepted that TM ions, when incorporated into the ZnO lattice, are isovalent with the zinc ions they substitute for. Thus, Mn in ZnO is commonly present in the divalent charge state for perceptibly high concentrations above 1019cm−3. However, recent electron paramagnetic resonance (EPR) experiments on ZnO with Mn traces of concentrations as low as 1014cm−3 suggest that the Mn charge state can deviate from the divalent configuration[2]. In order to elucidate stable valence configurations of Mn and their respective transition levels bandstructure calculations have been performed in the framework of density functional theory (DFT). The impact of additional on-site coulomb interaction within the local spin density approach (LSDA+U) will be discussed.
[1] T. Dietl et al., Science 287, 1019 (2000)
[2] M. A. Gluba et al., Superlattices and Microstructures (in press)