Electrically writing a magnetic heliknoton in a chiral magnet

Nature Materials (2026)Cite this article A magnetic heliknoton is the three-dimensional counterpart to the two-dimensional magnetic skyrmion, and serves as a pivotal topological soliton for extending topological magnetism into three dimensions. However, its experimental realization remains elusive. Here we report the controlled nucleation of a magnetic heliknoton in the chiral magnet FeGe at zero magnetic field, achieved through nanoscale current-pulse excitation. By combining angle-dependent quantitative electron holography with micromagnetic simulations, we resolve the three-dimensional spin texture of the heliknoton. In particular, the heliknoton exhibits current-driven collinear motion without the Hall effect. 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J.Z. was supported by the Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, US Department of Energy, under award number DE-SC0020221 and Alexander von Humboldt Foundation.Anhui Province Key Laboratory of Low-Energy Quantum Materials and Devices, High Magnetic Field Laboratory, HFIPS, Chinese Academy of Sciences, Hefei, ChinaLong Li, Shuisen Zhang, Ning Wang, Mingliang Tian, Yizhou Liu & Haifeng DuScience Island Branch of Graduate School, University of Science and Technology of China, Hefei, ChinaLong Li, Shuisen Zhang, Mingliang Tian & Haifeng DuInstitutes of Physical Science and Information Technology, Anhui University, Hefei, ChinaDongsheng Song & Weiwei WangSchool of Physics and Optoelectronic Engineering, Anhui University, Hefei, ChinaLingyao Kong & Mingliang TianSchool of Physical Science and Technology, ShanghaiTech University, Shanghai, ChinaShilei ZhangDepartment of Physics and Astronomy, University of New Hampshire, Durham, NH, USAJiadong ZangMaterials Science Program, University of New Hampshire, Durham, NH, USAJiadong ZangSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarH.D. conceived and supervised the project. Y.L. conceived the experimental heliknoton configuration. D.S. and H.D. designed the experiments. L.L. fabricated the FeGe devices. L.L., N.W. and D.S. performed the TEM experiments and data analysis. Y.L., W.W. and L.K. performed the micromagnetic simulations. Y.L., Shuisen Z. and J.Z. developed the analytical formalism. Y.L., H.D., D.S. and L.L. prepared the manuscript with inputs from J.Z., Shilei Z. and M.T.Correspondence to Dongsheng Song, Yizhou Liu or Haifeng Du.The authors declare no competing interests.Nature Materials thanks the anonymous reviewers for their contribution to the peer review of this work.Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.a–c, Equi-spin surfaces of the heliknoton with mz = 0.2. The grey planes indicate the position of the cross-sectional cut. The spin helix’s q-vector is along the z-axis. d–f, Cross-sectional cut of the heliknoton in the xy-plane at layer z = -4 (layer counted from the central xy-plane, the thickness of each plane is 1 nm) (d), 0 (e), and 4 (f). A skyrmion-antiskyrmion pair can be clearly identified at layer z = 0 (the central xy-plane). For moving above or below the central plane, the spin configuration distorts in opposite manner and thus their magnetic contrasts mostly cancel each other out, resulting in what is shown in Figs. 1 and 2 of the main text at zero tilt angle. g–i, Cross-sectional cut of the heliknoton in the yz-plane at different x positions. j–l, Cross-sectional cut of the heliknoton in the xz-plane at different y positions.a, Minimal energy path between a heliknoton (0 in the reaction coordinate) and the spin helical state (1 in the reaction coordinate). b, Enlarged view of the minimal energy path in a around the energy barrier.a, Optical image of the tip of the Gatan TEM specimen holder, with the two middle electrodes of the chip connected to the sample holder using Cu wires. b, Overview of the four Au-electrode electrical chip, with the red rectangular box at the top indicating the placement position of the FeGe sample. The TEM FeGe microdevice was fabricated using a FIB-SEM dual-beam system. c, SEM image of the red-boxed region in b, where the Au electrodes and FeGe sample are connected via PtCx. Two Au electrodes, connected to PtCx, are used to apply a pulsed current to the FeGe sample during the experiment.a, b, SEM top view (a) and stereoscopic view (b) of the general sample with a tilt range of ±30° around x- and y-axis. c, d, SEM top view (c) and stereoscopic view (d) of the sample pre-tilted 30° around the x-axis. The sample can be tilted around the x-axis within a range of 0° to 60°, allowing a more detailed characterization of the heliknoton configuration. In b and d, the magnetic contrast of a heliknoton is schematically drawn to show the relative direction.a, Schematic of the rotation. b, \({m}_{z}\) component of the spin texture at the central plane during rotation, which shows a similar trend with the magnetic phase shown in Fig. 3 of the main text. The central plane is defined as the xy-plane that passes through the geometric center of the heliknoton. The scale bar is 200 nm.a, b, Over-focused (a) and under-focused (b) Lorentz TEM images of heliknoton at a defocus distance of 500 μm. c, d, The corresponding calculated phase-shift images (c) and in-plane magnetization mappings (d) calculated from TIE. The range of the tilt angle is from 0° to 50°. The scale bar is 100 nm.a, Schematic of the heliknoton dynamics driven by a current pulse applied along its torus-axis (y-axis). Color plots show the emergent magnetic field \({{B}_{z}^{e}={\boldsymbol{M}}}_{{\boldsymbol{0}}}\cdot \left({\partial }_{x}{{\boldsymbol{M}}}_{0}\times {\partial }_{y}{{\boldsymbol{M}}}_{0}\right)\) (\({{\boldsymbol{M}}}_{{\boldsymbol{0}}}\) is the local magnetic moment) at the center plane of heliknoton, which is opposite for the skyrmion and antiskyrmion. White dashed arrows show the direction of motion of skyrmion and antiskyrmion due to the skyrmion Hall effect. Black arrow represents the direction of motion of heliknoton. b, Snapshots of the heliknoton dynamics simulation with a current pulse along y-axis. The orientation of the heliknoton (defined as the normal vector of the equi-spin surface with \({m}_{z}=-0.8\)) is indicated by the grey arrow. c, The corresponding orientation (top), position (middle), and dilation (bottom) of heliknoton extracted from the simulations.a, Schematic of the heliknoton dynamics driven by a current pulse applied along x-axis. Color plots show the emergent magnetic field \({{B}_{z}^{e}={\boldsymbol{M}}}_{{\boldsymbol{0}}}\cdot \left({\partial }_{x}{{\boldsymbol{M}}}_{0}\times {\partial }_{y}{{\boldsymbol{M}}}_{0}\right)\) (\({{\boldsymbol{M}}}_{{\boldsymbol{0}}}\) is the local magnetic moment) at the center plane of heliknoton, which is opposite for the skyrmion and antiskyrmion. White dashed arrows show the direction of motion of skyrmion and antiskyrmion due to the skyrmion Hall effect. Black arrow represents the direction of motion of heliknoton. Orange arrow indicates the rotation of heliknoton in this case. b, Snapshots of the heliknoton dynamics simulation with a current pulse along x-axis. The orientation of the heliknoton is shown by the grey arrows. c, The corresponding orientation (top, defined as the normal vector of the equi-spin surface with \({m}_{z}=-0.8\)), position (middle), and dilation (bottom) of heliknoton extracted from the simulations. Orange and black arrows label the time when the current pulse is on and off, respectively.Representative snapshots of a single heliknoton motion from one corner to another corner of the system using successive current pulses. The red, purple, and blue arrows schematically indicate the moving trajectory. From the initial position to position 1, a current pulse with \(j=3\times {10}^{11}{\rm{A}}\, {{\rm{m}}}^{-2}\) was applied along the y-axis for 1 ns. After 15 ns, five current pulses with \(j=-5\times {10}^{10}{\rm{A}}\, {{\rm{m}}}^{-2}\) were applied along the z-axis with 1 ns duration and 10 ns intervals to drive the heliknoton to position 2. Finally, three current pulses with \(j=-5\times {10}^{11}{\rm{A}}\, {{\rm{m}}}^{-2}\) were applied along the x-axis with 1 ns duration and 20 ns intervals to drive the heliknoton to position 3. The simulated system size is 1050 × 1050 × 600 nm3. A movie of this process can be found in Supplementary Video 9.Supplementary Figs. 1–13 and Sections 1–8.Creation of an isolated heliknoton with current pulses. The pulse duration is 40 ns, and the current density is \(6.86\times {10}^{10}\,{\rm{A}}\, {{\rm{m}}}^{-2}\).Current-induced creation of a heliknoton coexisting with other spin textures. The pulse duration is 40 ns, and the current density is \(6.98\times {10}^{10}\,{\rm{A}}\, {{\rm{m}}}^{-2}\).Creation of a heliknoton coexisting with other spin textures at a different current density. The pulse duration is 40 ns, and the current density is \(7.03\times {10}^{10}\,{\rm{A}}\, {{\rm{m}}}^{-2}\).Current-pulse-induced motion of a heliknoton in the flow regime. The heliknoton moves steadily and collinearly with the current direction. The pulse duration is 20 ns, and the current density is \(8.47\times {10}^{10}\,{\rm{A}}\, {{\rm{m}}}^{-2}\).Current-pulse-induced motion of a heliknoton in the creep regime. In this case, the trajectories of the heliknoton are not well defined and deviate from the collinear alignment with the current direction. The heliknoton exhibits hopping-like behaviour in its trajectory due to pinning effects. The pulse duration is 20 ns, and the current density is \(6.54\times {10}^{10}\,{\rm{A}}\, {{\rm{m}}}^{-2}\).Current-pulse-induced motion of a heliknoton in the flow regime. The pulse duration is 40 ns, and the current density is \(6.11\times {10}^{10}\,{\rm{A}}\, {{\rm{m}}}^{-2}\).Simulated current-pulse-induced heliknoton motion. The heliknoton moves collinearly with the current direction. The pulse duration is 9 ns, and the current density is \(1\times {10}^{11}\,{\rm{A}}\, {{\rm{m}}}^{-2}\).Simulated entangled translation–rotation of heliknoton. The applied current direction is perpendicular to the original orientation of the heliknoton. The orientation of the heliknoton eventually aligns with the current direction. The pulse duration is 1 ns, and the current density is \(5\times {10}^{11}\,{\rm{A}}\, {{\rm{m}}}^{-2}\).Simulated 3D dynamics of a heliknoton. By applying a series of current pulses in different directions, the heliknoton moves from one corner of the system to another. Detailed current pulse information is provided in the Methods and Extended Data Fig. 9.Current-driven motion of two isolated heliknotons. The current density is 8.09 × 1010 A m−2 and the pulse duration is 20 ns.Collective motion of two heliknotons that initially form a heliknoton dimer. The current density is 7.05 × 1010 A m−2, with a pulse duration of 20 ns.Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.Reprints and permissionsLi, L., Song, D., Wang, W. et al. Electrically writing a magnetic heliknoton in a chiral magnet. Nat. Mater. (2026). https://doi.org/10.1038/s41563-025-02450-0Download citationReceived: 18 March 2025Accepted: 18 November 2025Published: 07 January 2026Version of record: 07 January 2026DOI: https://doi.org/10.1038/s41563-025-02450-0Anyone you share the following link with will be able to read this content:Sorry, a shareable link is not currently available for this article. Provided by the Springer Nature SharedIt content-sharing initiative