Dresden 2026 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 8: Altermagnets II

MA 8.4: Vortrag

Montag, 9. März 2026, 15:45–16:00, HSZ/0002

Broadband nonlinear Hall response and multiple wave mixing in a room temperature altermagnet — •Berthold Jaeck — HKUST, Department of Physics, Clear Water Bay, Kowloong, Hong Kong

Altermagnets are characterized by magnetic crystal order that manifests in a non-relativistic spin-splitting of the electronic bands. Their electric material properties should thus be determined by the underlying symmetries. We report the discovery of a broadband third-order nonlinear anomalous Hall effect in altermagnetic CrSb at room temperature that exhibits a distinct spatial anisotropy [1]. The comparison of our experimental observations with symmetry analyses and model calculations shows that this nonlinear Hall response is induced by the nonlinear electric susceptibility of a Berry curvature quadrupole. This quadrupole precisely reflects the magnetic and crystalline symmetries encoded in the altermagnetic g-wave order parameter. We then utilize the nonlinear electric susceptibility of CrSb to realize a multiple wave mixing device with pronounced four wave mixing output. Our study provides a generalized understanding of the impact of magnetic crystal order on the electric material properties of altermagnets and significantly expands their technological scope to include high-frequency applications up to the THz regime.

We acknowledge funding by the Hong Kong RGC (Grant Nos.26304221, 16302422, 16302624, and C6033-22G) and the Croucher Foundation (Grant No.CIA22SC02).

[1] S. Sankar et al., arXiv:2511.10471 [cond-mat.mes-hall] (2025)

Keywords: Altermagnet; Nonlinear Hall effect; Berry curvature quadrupole; Multiple wave mixing