condensed matter physics

Visualizing spin-polarization of an altermagnet KVSeO via spin-selective tunneling

arXiv:2603.21969

summary

The authors use spin-selective scanning tunneling microscopy with a topological‑insulator tip to directly image the momentum‑dependent d‑wave spin polarization in the metallic altermagnet KV₂Se₂O.

Abstract

Altermagnetism, a recently identified magnetic phase that combines vanishing net magnetization with momentum-dependent spin splitting, challenges the conventional dichotomy between ferromagnets and antiferromagnets. While several candidate materials have been proposed, direct experimental evidence linking crystal symmetry, electronic structure and d-wave spin polarization remains scarce. Here we report the visualization of a metallic d-wave altermagnet in KV2Se2O. Through spin-selective scanning tunneling microscopy powered by a topological insulator tip, we uncover symmetry-protected momentum-dependent spin splitting that follows a characteristic d-wave form factor. Our results establish KV2Se2O as a tunable platform to study the interplay between spin-valley locking, Fermi-surface instability and unconventional magnetism, and open a pathway toward symmetry-engineered spintronics without net magnetization.

17 pages, 4 figures; Comments are welcome

Topics & keywords

#altermagnetism#spin‑polarized STM#d‑wave spin splitting#KV2Se2O#symmetry‑protected spin texturealtermagnetKV2Se2Ospin‑selective scanning tunneling microscopytopological insulator tipd‑wave spin polarizationmomentum‑dependent spin splitting