Regensburg 2022 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 31: Topological Insulators (joint session MA/KFM)
MA 31.9: Vortrag
Donnerstag, 8. September 2022, 17:15–17:30, H37
Topology, Colossal Magnetoresistance, and Complex Magnetic Domains in Eu5In2Sb6 — •Marein Rahn1,2, Murray N. Wilson3, Priscila F. S. Thomas2, Tom Lancaster3, Filip Ronning2, and Marc Janoschek4,5 — 1IFMP, TU Dresden, 01062 Dresden, Germany — 2LANL, Los Alamos, New Mexico 87545, USA — 3Department of Physics, Durham University, Durham, DH1 3LE, UK — 4Laboratory for Neutron and Muon Instrumentation, Paul Scherrer Institute, CH-5232 Villigen, Switzerland — 5Physik-Institut, U. Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
The axion insulating state is a paradigm of topological correlated matter which has been particularly difficult to demonstrate in real materials. Using neutron scattering, resonant elastic x-ray scattering, muon spin-rotation and bulk measurements, we demonstrate how the combination of co-planar glide symmetries and large Eu2+ magnetic moments in the Zintl phase Eu5In2Sb6 produces an unusual two-step ordering process. At 14 K, Eu5In2Sb6 first forms a complex non-collinear weak Ising-ferrimagnet, which we identify as a trivial insulator. Below 7.5 K, this phase is continuously displaced by a growing volume fraction of a compensated antiferromagnetic arrangement that may have axion insulating character. This discovery also implies the presence of a solitonic antiferromagnetic domain structure on the mesoscale, which demonstrably couples to charge transport and, due to the net magnetization of some domains, should be highly susceptible to manipulation. This may open up a platform to engineer interfaces of trivial and non-trivial insulators on the mesoscale.