Intricate Magnetic Landscape in Antiferromagnetic Kagome Metal TbTi₃Bi₄ and Interplay with Ln_2–xTi_6+xBi₉ (Ln: Tb···Lu) Shurikagome Metals

Here we present the discovery and characterization of the kagome metal TbTi 3 Bi 4 in tandem with a new series of compounds, the Ln 2 – x Ti 6+ x Bi 9 (Ln: Tb–Lu) shurikagome metals. We previously reported on the growth of the LnTi 3 Bi 4 (Ln: La–Gd 3+, Eu 2+, Yb 2+ ) family, a chemically diverse and exfoliable series of kagome metals with complex and highly anisotropic magnetism. However, unlike the La–Gd analogs, TbTi 3 Bi 4 cannot be synthesized by our previous methodology due to phase competition with crystals of Ln 2 – x Ti 6+ x Bi 9 ( x ∼ 1.7–1.2). Here we discuss the phase competition between the LnTi 3 Bi 4 and Ln 2 – x Ti 6+ x Bi 9 families, helping to frame the difficulty in synthesizing LnTi 3 Bi 4 compounds with small Ln species and providing a strategy to circumvent the formation of Ln 2 – x Ti 6+ x Bi 9 . Detailed characterization of the magnetic and electronic transport properties on single crystals of TbTi 3 Bi 4 reveals a highly complex landscape of magnetic phases arising from an antiferromagnetic ground state. A series of metamagnetic transitions creates at least 5 unique magnetic phase pockets, including a 1/3 and 2/3 magnetization plateau. Further, the system exhibits an intimate connection between the magnetism and magnetotransport, exhibiting sharp switching from positive (+40%) to negative magnetoresistance (−50%). Like the LnTi 3 Bi 4 kagome metals, the Ln 2 – x Ti 6+ x Bi 9 family exhibits quasi-2D networks of titanium and chains of rare earth. We present the structures and some basic magnetic properties of the Ln 2 – x Ti 6+ x Bi 9 family alongside our characterization of the newly discovered TbTi 3 Bi 4 .