Author(s): Ling-Fang Lin, Yang Zhang, Satoshi Okamoto, Adriana Moreo, Lun-Hui Hu, and Elbio Dagotto Altermagnetism—moment-compensated magnetism with momentum-dependent spin splitting—has so far been realized primarily in Néel-type antiferromagnets. Here, we demonstrate altermagnetism in folded iron chain systems with block-type magnetic order (e.g.,$↑↑↓↓$). In the strictly one-dimensional (1D) cas… [Phys. Rev. Lett. 137, 176702] Published Thu Oct 22, 2026