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Kagome metals provide a versatile platform for exploring the interplay of magnetism and topological electronic phenomena. Recent studies have revealed intriguing electronic reconstruction due to magnetic orders of rare earth moments in titanium-based kagome antiferromagnetic LnTi3Bi4[1-3] (Ln = rare earth). Although various magnetic orders have been revealed by various transport and magnetometry measurements, the direct observation of these spin modulations in real space remains elusive. Herein, we report stripe-like spin density waves (SDW) on the surface of TbTi₃Bi₄ using spin-polarized scanning tunneling microscopy (SP-STM)[4]. We observed the commensurate (1/3, 0, 0) SDW that is consistent with the band folding revealed by angle-resolved photoelectron spectroscopy. In addition, our SP-STM data also reveal an incommensurate SDW with the wavevector matching that of the bulk magnetic order[4]. The co-existence of commensurate and incommensurate SDWs provide new insights for understanding giant anomalous Hall effect due to strong spin-charge coupling in TbTi₃Bi₄.

[1] A. P. Sakhya et al. Diverse electronic landscape of the kagome metal YbTi₃Bi₄. Commun. Mater. 5, 241 (2024).

[2] P. Park et al. Spin density wave and van Hove singularity in the kagome metal CeTi₃Bi₄. Nat. Commun. 16, 4384 (2025)

[3] R. Zhang et al. Observation of orbital-selective dual modulations in an anisotropic antiferromagnetic kagome metal TbTi₃Bi₄. Phys. Rev. X 15, 031012 (2025).

[4] E. Cheng et al. Interwoven magnetic kagome metal overcomes geometric frustration. Nat. Mater. Accepted (2025).