Berlin 2018 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 20: Topological Semimetals II
TT 20.6: Vortrag
Montag, 12. März 2018, 16:15–16:30, A 053
An optical investigation of the strong spin-orbital coupled magnetic semimetal YbMnBi2 — •Alexander Yaresko1, Dipanjan Chaudhuri2, Bing Cheng2, N. Peter Armitage2, Quinn D. Gibson3, and Robert J. Cava3 — 1Max-Planck-Institute for Solid State Research, Heisenbergstrasse 1, 70569 Stuttgart, Germany — 2Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, MD 21218, USA — 3Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
Strong spin-orbit coupling can result in ground states with non-trivial topological properties. The situation is even richer in magnetic systems where the magnetic ordering can potentially have strong influence over the electronic band structure. The class of AMnBi2 (A = Sr, Ca) compounds are important in this context as they are known to host massive Dirac fermions with strongly anisotropic dispersion, which is believed to be due to the interplay between strong SOC and magnetic degrees of freedom. We report the optical conductivity of YbMnBi2, a newly discovered member of this family and a proposed Weyl semi-metal candidate with broken time reversal symmetry. Comparing experimental and theoretical optical spectra we show that the complex conductivity can be interpreted as the sum of an intra-band Drude response and inter-band transitions. We find signatures of a gapped Dirac dispersion, common in other members of AMnBi2 family or compounds with similar 2D network of Bi atoms.