December 22, 2025 -- Kagome lattices—networks of corner-sharing triangles—are known to host exotic quantum states, including topological electronic phases and unconventional magnetism. However, in conventional magnetic kagome materials, geometric frustration severely restricts the types of magnetic order that can form, limiting their functional tunability.

The newly discovered material TbTi₃Bi₄  - a new member of the kagome metals family - breaks this paradigm. Instead of placing magnetic atoms directly on the kagome lattice, the researches  employed an interwoven structural design:

- Magnetic terbium (Tb) atoms form quasi-one-dimensional zigzag chains

- Non-magnetic titanium (Ti) kagome bilayers host itinerant electrons

This separation of magnetic and electronic subsystems lifts geometric frustration while maintaining strong coupling between magnetism and charge transport.

Exceptional magneto-transport properties

Using a combination of angle-resolved photoemission spectroscopy (ARPES), spin-polarized scanning tunnelling microscopy, neutron diffraction, and transport measurements, the team led by Dr. Erjian Cheng uncovered an unusual coexistence of:

- A complex elliptical-spiral magnetic order with very large magnetic moments

- A coupled spin-density-wave electronic state

- A remarkably large electronic band-folding gap of ~90 meV.

Most strikingly, TbTi₃Bi₄ exhibits a giant anomalous Hall conductivity of up to 10⁵ Ω⁻¹ cm⁻¹, far exceeding values observed in conventional kagome magnets and even surpassing theoretical expectations based solely on Berry curvature effects. “This is a completely new route to achieving giant anomalous Hall effects,” says Dr. Erjian Cheng, group leader of the Thermoelectrics & Topology Group at the Max Planck Institute for Chemical Physics of Solids (MPI CPfS). “By interweaving separately designed magnetic and charge layers, we can overcome geometric frustration and unlock electronic responses that were previously inaccessible.”

Implications for quantum materials design

The findings establish TbTi₃Bi₄ as a benchmark system for studying strong electron–magnetism coupling in kagome metals and demonstrate a general design principle for engineering emergent quantum states. “This work shows that kagome physics does not have to be limited by frustration,” says Prof. Claudia Felser, Director at MPI CPfS and co-author of the study. “It opens new opportunities for designing materials with tailored magneto-transport properties relevant for future quantum and spintronic technologies.”

Outlook: Toward spintronic functionalities at elevated temperatures

Beyond its fundamental significance, the discovery of TbTi₃Bi₄ opens a promising pathway toward spintronic applications, where efficient control of spin currents is essential. The interwoven architecture—combining quasi-one-dimensional magnetic chains with a conducting kagome lattice—offers an unusual platform in which magnetism, topology, and electronic transport can be engineered largely independently.

Kagome metals are known to host strong Berry curvature, which underpins large anomalous Hall and spin Hall effects. In TbTi₃Bi₄, this Berry curvature is strongly enhanced by the coupling to robust magnetic order originating from the one-dimensional Tb chains. Such a combination is highly attractive for spintronics, as it can lead to enhanced spin–orbit torques, efficient charge-to-spin conversion, and large spin Hall responses—key ingredients for low-power magnetic memory and logic devices.

Importantly, the design principle demonstrated here is not restricted to terbium-based compounds. By selecting magnetic ions and kagome layers with higher ordering temperatures and stronger spin–orbit coupling, this interwoven strategy could be extended toward room-temperature operation. The ability to separately tailor magnetic chains and kagome-derived electronic states provides a new materials-by-design route for realizing topological spintronic devices, where Berry-curvature-driven effects amplify spin transport far beyond conventional limits.

“This work shows how low-dimensional magnetism and kagome topology can be combined to boost spin-dependent transport,” says Erjian Cheng. “It points toward a new class of quantum materials in which enhanced spin–orbit torques and spin Hall effects may be realized through deliberate structural design.”