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MA: Fachverband Magnetismus

MA 37: Magnetic Semiconductors II

MA 37.3: Vortrag

Mittwoch, 16. März 2011, 15:15–15:30, HSZ 401

Magnetic properties of ZnO based diluted magnetic semiconductors using hybrid functional DFT — •Sanjeev K. Nayak, Heike C. Herper, Markus E. Gruner, and Peter Entel — Faculty of Physics, University of Duisburg-Essen, 47057 Duisburg

We study the magnetic properties of diluted magnetic semiconductor based on ZnO with transition metal dopants (Cr, Fe, Mn, Co and Ni) using the hybrid functional treatment in density functional theory (PBE0 [1], HSE [2]). At first the electronic structure using a semiconductor supercell is studied with the hybrid functional. Thereafter the dopants are substituted in the cation lattice sites, structurally relaxed and their magnetic properties are investigated. We mostly focus on the nearest neighbor interactions of the dopant atoms. Our preliminary results show that out of the two similar nearest neighbors (nn) in ZnO, the one lying along the c-axis favors a ferromagnetic alignment of Co spins and the other nn along the hexagonal plane favors antiferromagnetic interaction in GGA. However, both the nn separations stabilize antiferromagnetic interaction in hybrid functional calculations. This is similar to what is obtained when the Hubbard correlation U is added to the system. We compare the GGA+U and the hybrid functional results. All our studies are done with the Vienna ab-initio simulation package (VASP [3]).

[1] Paier et al., J. Chem. Phys. 122, 234102 (2005), [2] Paier et al., J. Chem. Phys. 124, 154709 (2006), [3] Kresse et al., Phys. Rev. B 54, 11169 (1996)