# Extended s-wave altermagnets

## TL;DR

This paper introduces extended s-wave altermagnets (sAMs), a new class of magnetic states with unique spin and electronic properties, formed via valley-exchange symmetries, with potential for spintronic applications.

## Contribution

The paper defines sAMs, demonstrates their properties using models, and provides principles to identify them in quantum magnets, expanding the understanding of magnetic states.

## Key findings

- sAMs are fully gapped and spin-compensated with spin-polarized bands.
- sAMs exhibit isotropic spin splitting and enable spin-selective transport.
- sAMs can give rise to descendant pair density wave order.

## Abstract

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.