Title: Anomalous Spin Transport in Collinear Antiferromagnets: Molecular Conductors and Perovskites
When: Wednesday, July 05, (2023), 12:00
Place: Department of Theoretical Condensed Matter Physics, Faculty of Sciences, Module 5, Seminar Room (5th Floor).
Speaker: Hitoshi Seo, Condensed Matter Laboratory, RIKEN, Wako, Saitama 351-0198, Japan.
We theoretically propose novel spin transport properties in materials showing magnetic order with antiparallel spin configuration, i.e., collinear antiferromagnets. The combination of simple spin order and characteristic crystal structures can give rise to spin transport with a novel mechanism. Our first observation is the existence of a nontrivial spin-dependent energy band structure (spin splitting), found in the effective model of a well-known kappa-type BEDT-TTF molecule-based crystals[1,2]. This gives rise to spin-polarized current when an electric field or thermal gradient is applied to the sample. Another predicted pheno-menon is the anomalous Hall effect, which is the Hall effect without applying magnetic field conventionally discussed in ferromagnetic materials; here the net magnetization is not required, and the antiparallel spin order is its source. These phenomena can be applied to any system with the required conditions fulfilled, and we indeed demonstrate analogous behavior in perovskite metal oxides.
- M. Naka et al., Nat. Commun. 10, 4305 (2019).
- H. Seo and M. Naka, J. Phys. Soc. Jpn. 90, 064713 (2021).
- M. Naka et al., Phys. Rev. B 102, 075112 (2020).
- M. Naka, Y. Motome, and H. Seo, Phys. Rev. B 103, 125114 (2021); Phys. Rev. B 106, 195149 (2022).