Localized helical spin texture in ferromagnetic thin films
Xiao-Qi Cui (Peng Huanwu Center for Fundamental Theory, Xi’an, 710127, China, School of Physics, Northwest University, Xi’an, 710127, China)
; Xin-Wei Jin (Department of Physics, Zhejiang Normal University, Jinhua, 321004, China); Shiyi Wang (Peng Huanwu Center for Fundamental Theory, Xi’an, 710127, China, School of Physics, Northwest University, Xi’an, 710127, China); Xiao-Yong Wen (School of Applied Science, Beijing Information Science and Technology University, Beijing, 100192, China); Zhan-Ying Yang (Shaanxi Key Laboratory for Theoretical Physics Frontiers, Xi’an, 710127, China, Peng Huanwu Center for Fundamental Theory, Xi’an, 710127, China, School of Physics, Northwest University, Xi’an, 710127, China)
Based on a continuous spin dynamics model of two-dimensional ferromagnetic thin films, we employ a gauge equivalence approach to transform the spin dynamical equations into analytically tractable scalar forms, establishing a constructive framework that directly links spin dynamics to real-space spin configurations. Within this framework, we construct and analyze localized helical spin textures, whose magnetization is confined within a finite spatial region while the spin orientation undergoes continuous rotation, giving rise to a well-defined chirality. These textures can be classified into three fundamental types: left-handed helices, right-handed helices, and mixed helices. We further show that multiple localized helical textures can coexist and form composite configurations under nonlinear dynamical constraints, leading to distinct bound states composed of textures with the same or opposite chirality. These results identify localized helical spin textures as a class of fundamental nonlinear magnetic excitations in two-dimensional ferromagnetic systems, and provide a concrete analytical route for understanding the emergence and combination of chiral spin structures beyond periodic magnetic order.
