标题： 扩展的s波反铁磁体 显示英文标题

标题： Extended s-wave altermagnets

摘要： 我们提出扩展的s波反铁磁体（sAMs）作为一个磁态类别，其特点是完全禁带、自旋补偿，并具有自旋极化能带。 sAMs是通过谷交换对称性形成的，这些对称性作为动量空间平移，超越了标准晶体学自旋群分类。 使用一个有效的两谷模型，我们证明sAMs表现出各向同性的自旋分裂，在定制异质结构中实现自旋选择性输运，并产生后代对密度波序。 从一个微观的sAM最小模型出发，我们开发了在量子磁体中识别sAMs的指导原则。 显示英文摘要

摘要： We propose extended s-wave altermagnets (sAMs) as a class of magnetic states which are fully gapped, spin-compensated, and feature spin-polarized bands. sAMs are formed through valley-exchange symmetries, which act as momentum-space translations beyond standard crystallographic spin-group classifications. Using an effective two-valley model, we demonstrate that sAMs exhibit isotropic spin splitting, enable spin-selective transport in tailored heterostructures, and give rise to descendant pair density wave order. From a microscopic sAM minimal model, we develop the guiding principles to identify sAMs in quantum magnets.