Dresden 2026 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 21: Electron Theory of Magnetism and Correlations (joint session MA/TT)
TT 21.3: Vortrag
Montag, 9. März 2026, 15:30–15:45, POT/0151
Ground State of the Topological Insulator Candidate Eu2AuGe3 — •Vinicius Estevo Silva Frehse1, Aleksandr Sukhanov1, Artem Korshunov2, Eugen Weshcke3, Aly Abdeldaim4, Priscila Rosa5, and Marein Rahn1 — 1Universität Augsburg, Augsburg, Germany — 2Donostia International Physics Center, San Sebastián, Spain — 3Helmholz Zentrum Berlin, Berlin, Germany — 4Diamond Light Source, Didcot, UK — 5Los Alamos National Laboratory, Los Alamos, USA
Eu2AuGe3 is an unusual rare earth germanide in which quasi-trigonal europium sheets are interleaved with Au-Ge honeycomb layers, where high-throughput calculations indicate potential for topological band inversions. Bulk and transport data have revealed a series of (re-)ordering transitions upon cooling, as well as metamagnetic transitions at low temperature. Recently, we identified a broad transition around TCDW = 130 K as the continuous freezing-out of a buckling mode of the honeycomb layers.
Here, we present preliminary evidence from neutron and resonant elastic X-ray scattering, which hints at helical magnetic order below TN = 11 K. Unexpectedly for the nominally spin-only divalent europium, the magnetic order also appears to be accompanied by a modulated orbital order parameter. This phase is preceded by a transition at 23 K, where we observe a subtle doubling of the ab-plane, possibly related to the charge density wave formed during TCDW.
Keywords: Helical magnetism; Rare-earth intermetallics; Resonant scattering; Neutron scattering; Topological materials