Regensburg 2016 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 78: Correlated Electrons: Poster Session

TT 78.52: Poster

Donnerstag, 10. März 2016, 15:00–18:30, Poster D

Dimensional crossover in manganese based analogues of iron pnictides — •Manuel Zingl, Elias Assmann, and Markus Aichhorn — Institute of Theoretical Physics and Computational Physics, NAWI Graz, Graz University of Technology, Petersgasse 16, 8010 Graz, Austria

The manganese pnicitides BaMn₂As₂ and LaOMnAs crystallize in the same structure as the extensively studied iron pnictide high-temperature superconductors BaFe₂As₂ and LaOFeAs. In contrast to the d⁶ configuration of the iron systems, the manganese d-shell is only half-filled (d⁵). As a consequence, electronic correlations are much stronger, placing these compounds at the verge of the Mott metal-insulator transition. In this region of the phase diagram materials are prone to enhanced magnetism, apparent in the remarkably high Néel temperature of 625 K for BaMn₂As₂. We demonstrate that the experimentally observed differences in the Néel temperatures, the band gap, and the optical properties of the manganese compounds under consideration can be traced back to their effective dimensionality. Our fully charge self-consistent DFT+DMFT calculations show excellent agreement with experiments, especially measured optical spectra.