Edge spin galvanic effect in altermagnets

The edge spin galvanic effect (ESGE) in $d$-wave altermagnets is proposed. ESGE is a creation of an electrical current flowing along the edge of the sample, which is driven by the spin orientation of charge carriers. The ESGE current is formed owing to the altermagnetic spin splitting and the scattering of carriers by the edge of the sample. The current is sensitive to the orientation of the edge in respect to the main axes of the altermagnet. The edge spin galvanic current reverses its direction upon a reversal of the non-equilibrium spin direction or the Néel vector. We also propose the pure spin edge photocurrent excited by polarized radiation and formed at the edges of a sample. Its dependence on the radiation polarization and frequency is analyzed. The application of an external magnetic field converts this pure spin photocurrent into an electric current along the edge.