An international team has uncovered a complex network of topological electronic states inside cobalt that remain stable at room temperature. The finding challenges decades of assumptions about the well-studied metal and points to potential uses in spintronics and quantum technologies.
Researchers led by Dr. Jaime Sánchez-Barriga at Helmholtz-Zentrum Berlin used spin- and angle-resolved photoemission spectroscopy at the BESSY II facility to map cobalt's electronic structure. They identified multiple magnetic nodal lines where spin-polarized states intersect without forming gaps. These crossings allow electrons to behave like massless particles and travel at high speeds in certain crystal directions. The spin polarization can be reversed by changing the material's magnetization direction. First-principles calculations by a team including Dr. Maia G. Vergniory confirmed the experimental results and showed that crystalline mirror symmetries protect the nodal lines. The study was published in Communications Materials in 2026. The work involved scientists from institutions in Germany, Spain, the United Kingdom, and Canada. It suggests that other familiar ferromagnetic metals may harbor similar hidden quantum features.
