Spin-polarized electron transport for the altermagnet CrSb

We experimentally investigate spin-polarized electron transport for the centrosymmetric altermagnet CrSb, which is known to reveal both altermagnetic and topological features. We demonstrate pronounced first-harmonic anomalous and second-harmonic non-linear Hall effects for a single-crystal CrSb flake with ferromagnetic nickel contacts, while both effects can not be seen for the reference samples with non-magnetic gold ones. For the anomalous Hall effect, we demonstrate bow-tie hysteresis loop in Hall voltage, which is usually ascribed to surface spin textures in magnetic materials. The slope of the Hall curve changes a sign for two orientations of the Hall-bar contact configuration for the same sample, i.e. for the same sign of the charge carriers. We interpret the observed sign inversion and bow-tie hysteresis as the joint effect of the alternating bulk spin splitting and spin-polarized topological surface states in CrSb. The pronounced non-linear Hall effect with hysteresis in magnetic field confirms finite Berry curvature dipole under injection of spin-polarized electrons, i.e. the topological features for the altermagnetic candidate CrSb.