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TT: Fachverband Tiefe Temperaturen

TT 68: Superconductivity: Fe-based Superconductors - Theory I

TT 68.3: Vortrag

Mittwoch, 2. April 2014, 15:45–16:00, HSZ 201

Electronic and Magnetic Properties of Ba(Fe_1−xCo_x)₂As₂ — •Gerald Derondeau, Sergiy Mankovsky, Hubert Ebert, and Ján Minár — Department Chemie, Ludwig-Maximilians-Universität München, 81377 München, Germany

Characteristic for most iron arsenides is an antiferromagnetic ordering in form of a commensurate spin-density wave (SDW) at low temperatures, often coupled with a structural phase transition. Superconductivity emerges when these transitions are suppressed, e.g. by chemical doping. As many DFT calculations have still problems to accurately describe the magnetic state [1] further investigations on this issue are needed.

We investigated the low-temperature orthorhombic phase of Ba(Fe_1−xCo_x)₂As₂ using the Korringa-Kohn-Rostoker-Green function (KKR-GF) [2] approach which allows inclusion of chemical disorder via the coherent potential approximation (CPA). To examine the magnetic structure with different spin states we used a full magnetic unit cell with 8 Fe atoms and antiferromagnetic ordering. In addition spin-spiral calculations for the q-dependent induced magnetization were performed to account for the SDW state. Furthermore, the doping dependent evolution of the strong in-plane anisotropy of the electronic structure as observed in ARPES measurements [3] was investigated and connected to the magnetic behavior.
I. I. Mazin, M. D. Johannes, Nature Phys. 5, 141 (2009)
H. Ebert, D. Ködderitzsch, J. Minár, Rep. Prog. Phys. 74, 96501 (2011)
M. Yi, D. Lu, J.-H. Chu, et al., PNAS 108, 6878 (2011)