Chiral-bubble-induced topological Hall effect in ferromagnetic topological insulator heterostructures
Wenbo Wang, Yifan Zhao, Fei Wang, Matthew Daniels, Cui-Zu Chang, Jiadong Zang, Di Xiao, Weida Wu
The topological Hall effect (THE) is a transverse response of charge carriers due to emergent gauge field of non-coplanar spin textures. It has been a powerful tool to probe unconventional topological spin orders, such as the skyrmion crystal phase, in chiral magnets. However, there is mounting evidence that non-skyrmionic chiral spin textures, such as chiral domain walls, can result in a significant THE signal. \citejiang2020} Direct evidence of chiral domain walls in two- dimensional ferromagnets is still lacking. Here, we report the observation of low-temperature THE in the ferromagnetic ground state of a V-doped Sb$_2$Te$_3$ heterostructure with strong perpendicular magnetic anisotropy. The magnetization reversal process exhibits a typical ferromagnetic domain behavior with the formation of both nucleation bubbles and pinned bubbles. Topological Hall effects of opposite sign are directly correlated with the net curvature of domain walls in different domain configuration. The field dependence of the magnetization and topological Hall resistance is consistent with the integrated linear transport and Monte Carlo simulations, indicating these magnetic bubbles of opposite magnetization carry opposite topological charges. Our findings pave the way for the exploration and design of topological spin textures in two- dimensional ferromagnets.
, Zhao, Y.
, Wang, F.
, Daniels, M.
, Chang, C.
, Zang, J.
, Xiao, D.
and Wu, W.
Chiral-bubble-induced topological Hall effect in ferromagnetic topological insulator heterostructures, Nano Letters, [online], https://dx.doi.org/10.1021/acs.nanolett.0c04567, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=930544
(Accessed September 21, 2023)