Regensburg 2019 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 5: Superconductivity: Fe-based Superconductors - FeSe and 122
TT 5.10: Talk
Monday, April 1, 2019, 12:00–12:15, H23
Interplay of lattice, electronic, and spin degrees of freedom in detwinned BaFe2As2: A Raman scattering study — •Andreas Baum1,2, Ying Li3, Milan Tomić3, Nenad Lazarević4, Daniel Jost1,2, Florian Löffler1,2, Bernhard Muschler1, Thomas Böhm1,2, Jiun-Haw Chu5,6,7, Ian R. Fisher5,6, Roser Valentí3, Igor I. Mazin8, and Rudi Hackl1 — 1Walther-Meissner-Institut, 85748 Garching, Germany — 2Fakultät für Physik E23, Technische Universität München, 85748 Garching, Germany — 3Institut für Theoretische Physik, Goethe-Universität Frankfurt, 60438 Frankfurt am Main, Germany — 4Center for Solid State Physics and New Materials, Institute of Physics Belgrade, University of Belgrade, 11080 Belgrade, Serbia — 5SIMES, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA — 6GLAM and Department of Applied Physics, Stanford University, Stanford, CA 94305, USA — 7Department of Physics, University of Washington, Seattle WA 98195, USA — 8Code 6393, Naval Research Laboratory, Washington, DC 20375, USA
The magneto-structural phase transition of BaFe2As2 is studied by Raman spectroscopy with a focus on lattice dynamics. Using uniaxial pressure to detwin the sample allows us to resolve anisotropic features. The As A1g phonon shows a resonance at 3.1 eV with distinct differences between the antiferromagnetically and the ferromagnetically ordered direction. The Eg phonon at 130 cm−1 splits into two modes having B2g and B3g symmetry which differ by 10 cm−1. Both effects can be attributed to the emergence of magnetic order, rather than the structural transition, by DFT calculations.