Xingyue Yang, Shibo Fang, Zongmeng Yang, Pin Ho, Jing Lu, Yee Sin Ang
Giant Tunneling Magnetoresistance Flatband-engineered altermagnets open a new pathway for designing high-performance altermangetic tunnel junction. In the Research Article (DOI: 10.1002/adfm.202531921), Jing Lu, Yee Sin Ang, and co-workers show that nodal-like spin-degenerate intersections in KV2Se2O, a room-temperature d-wave altermagnet, effectively suppress antiparallel state leakage current, leading to record-high tunneling magnetoresistance in a magnetic tunnel junction device setup. These symmetry-protected flat Fermi sheets establish a Fermi-surface-geometry-driven design paradigm for next-generation spintronic and memory technologies.