Regensburg 2013 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 27: Superconductivity: Fe-based Superconductors - 122
TT 27.9: Talk
Tuesday, March 12, 2013, 12:00–12:15, H18
Effect of uniaxial stress and doping on structural and electronic properties of BaFe2As2 and CaFe2As2 — •Milan Tomic, Roser Valenti, and Harald O. Jeschke — Institut für Theoretische Physik, Goethe-Unversität Frankfurt, Max-von-Laue-Str. 1, 60438 Frankfurt, Germany
We investigate the effects of the uniaxial tensile and compressive stresses applied along a, b and a+b directions in BaFe2As2 and CaFe2As2 in the framework of ab initio density functional theory calculations. While the systems remain in the orthorhombic phase at moderate pressures, we observe an inversion of magnetism at a critical strain happening when the a and b axes approach the tetragonal condition. Furthermore, the doping-temperature-pressure phase diagrams of the 122 family of superconductors have been discussed intensively due to electronic nematicity above the structural and superconducting transition and the complex coupling between electronic and lattice degrees of freedom. We employ density functional theory to predict the structure of supercells of Ca1−xSrxFe2As2 and CaFe2(As1−xPx)2. We then predict structural transitions of the doped compounds under pressure and compare to the parent compound. We carefully analyze the changes in the electronic structure caused by doping and stress.