Combinatorics

Physics

Van Hove singularity

Electron

Topology (electrical circuits)

Mathematics

Ferromagnetism

Topological insulator

Neutrino

Spintronics

Magnetism

Surface (topology)

Geometry

Condensed matter physics

Fermi level

Spin (aerodynamics)

Dirac (video compression format)

Quantum mechanics

Surface states

Thermodynamics

Science Advances

Transition-metal-based kagome materials at van Hove filling are a rich frontier for the investigation of novel topological electronic states and correlated phenomena. To date, in the idealized two-dimensional kagome lattice, topologically Dirac surface states (TDSSs) have not been unambiguously observed, and the manipulation of TDSSs and van Hove singularities (VHSs) remains largely unexplored. Here, we reveal TDSSs originating from a ℤ2 bulk topology and identify multiple VHSs near the Fermi level (EF) in magnetic kagome material GdV6Sn6. Using in situ surface potassium deposition, we successfully realize manipulation of the TDSSs and VHSs. The Dirac point of the TDSSs can be tuned from above to below EF, which reverses the chirality of the spin texture at the Fermi surface. These results establish GdV6Sn6 as a fascinating platform for studying the nontrivial topology, magnetism, and correlation effects native to kagome lattices. They also suggest potential application of spintronic devices based on kagome materials.

Tunable topological Dirac surface states and van Hove singularities in kagome metal GdV <sub>6</sub> Sn <sub>6</sub>

Tunable topological Dirac surface states and van Hove singularities in kagome metal GdV 6 Sn 6

Tunable topological Dirac surface states and van Hove singularities in kagome metal GdV ₆ Sn ₆