Magnetism and topology in a novel Eu-based Zintl compound

Magnetic topological materials are a class of compounds in which the properties of the topology of their electronic band structure and their magnetic structure are strongly connected [1]. Recently, Eu-based Zintl compounds have been proposed as a novel bedrock for a plethora of magnetic topological phases [2-6]. In particular, Eu5In2As6 has been proposed as a potential candidate to show a C2T higher-order axion insulating phase, in which either the surface or the hinge states are determined by the symmetries of the surface termination [2]. In this work, we topotaxially converted thin films of Eu5In2As6 [7], and characterized them using magnetic susceptibility, scanning tunneling microscopy (STM), and magnetotransport. The system exhibits two antiferromagnetic transitions and a spin-polarized phase at higher fields. Each one of these phases has signatures in spectroscopy and response including gap closing and corresponding evolution of Shubnikov-de Haas oscillations as well as a peculiar anomalous Hall signal.

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[2] Zhao et al. arXiv preprint arXiv:2403.06304 (2024)

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[4] Yang Zhang et al. Phys. Rev. B 101, 205126 (2020).

[5] Takafumi Sato et al Phys. Rev. Research 2, 033342 (2020).

[6] Varnava et al. Phys. Rev. B 105, 235128 (2022).

[7] Song et al. Nat. Nanotechnol. (2024).