Contrasting in-plane anomalous Hall response observed in EuA₂Sb₂ (A=Zn, Cd) thin films

Recent observation of the in-plane anomalous Hall effect in magnetic Weyl semimetal EuCd₂Sb₂, with a trigonal lattice structure, has attracted interest in how an in-plane field can generate out-of-plane orbital magnetization [1]. In this work, we focus on EuZn₂Sb₂, a sister compound of EuCd₂Sb₂, to show how the in-plane anomalous Hall effect is sensitive to changes in the band structure and its quantum geometry. When measuring the Hall resistivity while rotating the field within the (001) plane of EuZn₂Sb₂ film, we see a clear three-fold component corresponding to the in-plane anomalous Hall effect, along with a two-fold component from the planar Hall effect. The in-plane anomalous Hall effect in EuZn₂Sb₂ behaves differently from EuCd₂Sb₂, especially in the sign and non-monotonic field dependences. This difference can be explained by model calculations with different band inversion parameters. Our results suggest that designing orbital magnetization by tuning the band structure will be possible through the observation of the in-plane anomalous Hall effect.

[1] A. Nakamura et al., arXiv:2405.16722 (2024).