Magnetic Super-modulation in Kagome Antiferromagnetic Metal TbTi₃Bi₄

Kagome metals with 2-dimensional network of corner sharing triangles have emerged as a promising platform to explore the interplay between topology and strong correlations due to geometric frustration. The LnTi₃Bi₄ (Ln = La, Ce, …) family are Kagome metals with quasi-one-dimensional spin-chains running along the a-axis. Complex magnetic phase diagrams were reported in some members of the family. Thus, it provides a playground to explore the interplay between magnetism and electronic structure, which might result in non-trivial topology. We perform spin polarized scanning tunneling microscopy (SP-STM) studies on a newly synthesized kagome metal TbTi₃Bi₄. The system orders antiferromagnetically below T_N=20 K. Our SP-STM results reveals the magnetic super-modulation at low temperature, confirming the antiferromagnetic ordering. The modulation wave vector agrees with the nesting of quasi-one-dimensional band structure observed in preliminary angle-resolved photoemission spectroscopy, supporting the strong coupling between magnetism and electronic band structure in kagome antiferromagnetic metal TbTi₃Bi₄.