Local signatures of altermagnetism

Studying altermagnets experimentally is challenging, especially when their macroscopic properties, such as spin-split bands and spin currents, average out due to domain structures. The authors demonstrate here how nonmagnetic impurities can serve as local probes to reveal the altermagnetic order. Impurities imprint a distinct signature on the local density of states that reflects the underlying momentum structure of the altermagnet, such as $d$-wave or $g$-wave. In proximity to a superconductor, these effects can be enhanced at bound states inside the superconducting gap.