Regensburg 2016 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 79: Superconductivity: Fe-based Superconductors - 122
TT 79.8: Vortrag
Donnerstag, 10. März 2016, 17:30–17:45, H21
Charge doping versus impurity scattering in substitutionally disordered Ba-122 — •Alexander Herbig1, Rolf Heid1, and Jörg Schmalian2,1 — 1Institut für Festkörperphysik, Karlsruher Institut für Technologie — 2Institut für Theorie der Kondensierten Materie, Karlsruher Institut für Technologie
The iron-based superconductors are a prominent example how chemical substitution can be used as a tuning parameter for the electronic properties and the superconductivity of a complex material. Until now, first principle calculations addressing disorder effects on the electronic structure via methods beyond supercells are rare. Also the role of doping and the impact of chemical substitution on superconductivity is not fully understood. Based on ealier work [1], we recently implemented Blackman, Esterling and Berk’s [2] extension of the coherent potential approximation within a pseudopotential framework using a linear combination of atomic orbitals basis. We present electronic structure calculations for the Ba-122 compound using this method with various species substitutions at different sites and arbitrary impurity concentrations. We focus on disorder effects on electron and hole bands near the Fermi level. We observe non-rigid level shifts and band selective broadenings due to impurity scattering which strongly depend on the substituent species [3]. Our finding of an enhanced intraband compared to interband scattering is in accordance with an s+− paring state.
[1] K. Koepernik et al., PRB 55, 5729 (1997)
[2] J. A. Blackman et al., PRB 4, 2412 (1971)
[3] A. Herbig et al., arXiv:1510.06941v1 (2015)