Powered by Indico
v3.2.3
The transverse current (jH) due to the anomalous Hall effect (AHE) is usually assumed to be perpendicular to the magnetization (m) in ferromagnetic materials, which governs the experiments in spintronics. Generally, this assumption is derived from a continuum model, where the crystal's discrete symmetry is effectively represented by the concept of an effective mass from the band structure. In this paper, we calculate the spin transport through the nonmagnetic metal (NM) | ferromagnetic metal (FM) interfaces and find that the corresponding Hall current is generally not perpendicular to m with only a few exceptions at high symmetry crystal orientations. The calculation illustrates the break down of jH=Θm×jc, where Θ denotes the anomalous Hall angle and jc represents the injecting charge current. This effect is further shown to arise from the in-plane rotational symmetry and the general existence of the interface chirality (IC) in the spin transport through NM|FM interfaces. The corresponding transmission probability (T) for specific Bloch state from the leads exhibits distinct values for different chiral states and the difference can be as large as ΔT/T≈78.4$ even for the well studied Cu|Co interface along fcc (111) direction, exhibiting giant IC effect. Our results highlight the significance of discrete atomic positions in solids for spin transport, which extends beyond the conventional continuum model. Moreover, considering the important application of the AHE in spintronics and the wide existence of the interfaces in the devices, this chiral anomalous Hall effect suggests that all experimental measurements related to the AHE should be re-evaluated.
[1] Di Xiao, Ming-Che Chang, and Qian Niu, Rev. Mod. Phys. 82, 1959 (2010).
[2] Naoto Nagaosa, Jairo Sinova, Shigeki Onoda, A. H. MacDonald, and N. P. Ong, Rev. Mod. Phys. 82, 1539 (2010).
Dr. Lei Wang obtained his bachelor's degree from the University of Science and Technology Beijing in 2012, and PhD from Beijing Normal University in 2017. He then began his postdoctoral research at Xi’an Jiao Tong University. In 2020, he was promoted to Associate Professor, and in 2023, he moved to Southeast University.
Dr. Wang's current research focuses on investigating emergent spin transport phenomena in various materials, including the anomalous Hall effect, spin Hall effect, spin-orbit torques, and spin pumping. His work explores these phenomena in interfaces, antiferromagnetic materials, and two-dimensional materials, considering factors such as temperature, disorder, and vacancies.
Tencent meeting link: https://meeting.tencent.com/dm/NFqkrhOuHEb5 Meeting ID: 168 487 375, no password