Dresden 2014 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 53: Superconductivity: Fe-based Superconductors - 122
TT 53.9: Talk
Wednesday, April 2, 2014, 11:45–12:00, HSZ 201
Effects of transition metal doping on the electronic structure of BaFe2As2 — •Jan Trinckauf1, Klaus Koepernik1, Sai Aswartham1, Vladimir Strocov2, Sabine Wurmehl1, Bernd Büchner1, and Jochen Geck1 — 1IFW Dresden, Germany — 2Paul-Scherrer Institute, Villigen, Switzerland
We have performed resonant soft X-ray ARPES measurements on Co and Ni doped BaFe2As2 on the L2,3 absorption edge of the dopant. We find that the 3d contribution of the TM dopant is shifted towards higher binding energies compared to the Fe bands and this shift increases with increasing atomic number. No considerable dispersion can be detected in the resonance features. We compared our data to DFT supercell calculations and see a similar trend in the 3d bandweights and the local DOS of the dopant. Most importantly, we observe in the calculations a shift of the Fermi level by the amount expected from the additional electrons on the TM sites, while simultaneously the total Fe 3d DOS stays constant. The additional electrons are counted solely towards the dopant. Referring to a model of local scatterers in a one-dimensional metallic chain and a two dimensional square lattice, we find that, while the electronic structure of the model as a function of the impurity potential behaves similar to what is observed in BaFe2As2, the effective doping behaves very different. This suggests that the almost rigid band like shift of the chimcal potential with doping, even in case of Cu, that is observed both theoretically and experimentally is a peculiarity of the compound, which has strong implications for the developement of superconductivity.