Electric and spin current vortices in altermagnets

Altermagnets are collinear magnets exhibiting momentum-dependent spin splitting and vanishing net magnetization. Using semiclassical Boltzmann and lattice Keldysh approaches, the authors demonstrate here that altermagnets support swirling electric and spin currents. The patterns of these currents are controlled by the relative orientation of altermagnetic nodal planes and sample boundaries. Unlike previous proposals considering the hydrodynamic transport regime, swirling currents appear even in the Ohmic regime and rely exclusively on altermagnetic spin splitting, with no swirls found in ferromagnets.