Dresden 2026 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 41: Topological Semimetals
TT 41.5: Vortrag
Mittwoch, 11. März 2026, 10:30–10:45, HSZ/0103
Large tunability of the magnetism in the Dirac semimetal EuMnBi2 under uniaxial pressure — •Caitlin I. O’Neil1, Hilary M.L. Noad1, Andrew P. Mackenzie1, Hideaki Sakai2, and Elena Gati1,3 — 1MPI-CPfS, Dresden — 2Tohoku University, Japan — 3Goethe University Frankfurt
Uniaxial pressure provides a controlled method for breaking lattice symmetries in crystals, and it has therefore become a powerful tool for tuning quantum materials. Although uniaxial-pressure techniques have been widely used in recent years to probe the coupling between correlated electrons and the lattice [1-2], their use to investigate the interplay between topological electrons, magnetism, and the lattice has been less common. We report on the discovery of a strong uniaxial pressure response in the magnetic Dirac semimetal EuMnBi2. In this material, there are layers of localised Eu2+ moments alternating with Bi square nets that host Dirac fermions. By measuring the AC Young’s modulus [3], we map out the phase diagram as a function of [1 0 0] uniaxial pressure and magnetic field, revealing a strong sensitivity of the Eu2+ magnetic order to strain, including the observation of multiple magnetic phases. We suggest that the pronounced tunability of the Eu2+ order arises from its coupling to a low-energy electronic structure that is sensitive to symmetry-breaking strains.
Work is supported by the DFG through TRR 288-422213477.
[1] Gati et al., Sci. Adv. 2, e1601646 (2016)
[2] Noad et al., Science 382, 447 (2023)
[3] O’Neil et al., RSI 95, 073909 (2024)
Keywords: Uniaxial stress; Young's modulus; Magnetism; Magnetoelastic coupling; Dirac semimetal