Dresden 2014 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 92: Superconductivity: Fe-based Superconductors - Theory II
TT 92.3: Talk
Thursday, April 3, 2014, 15:30–15:45, HSZ 201
BaFe2P2 and LaFe2P2: What makes the difference? — •Tobias Förster1, Helge Rosner2, Andrey Polyakov1, Marek Bartkowiak1, Andrea D. Bianchi3, and Jochen Wosnitza1 — 1Hochfeld-Magnetlabor Dresden (HLD), Helmholtz-Zentrum Dresden-Rossendorf, D-01328 Dresden, Deutschland — 2Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Str. 40, 01187 Dresden, Deutschland — 3Départment de Physique and RQMP, Université de Montréal, Montréal H3C 3J7, Canada
The Fermi-surface topology of iron-pnictide superconductors stimulated many theories on the pairing mechanism in these materials. Especially the degree of nesting between quasi-two-dimensional hole and electron bands is regarded as a key ingredient. However, also more localized pictures and the duality of both itinerant and localized degrees of freedom of the Fe 3d electrons are considered.To challenge the different scenarios, a precise knowledge of the electronic structure is necessary. We, therefore, present a detailed DFT study on LaFe2P2 and BaFe2P2. Using the full potential local orbital (FPLO) code we work out the difference between both compounds and show in detail what changes when replacing Ba with La. As a surprise, we find that a rigid-band-like description is inappropriate, since the La 5d states provide sizable contributions to a part of the Fermi surface. Additionally we use our de Haas-van Alphen measurements of LaFe2P2 and literature data of BaFe2P2 to refine our calculations and estimate the renormalization strength acting on the electronic structure.