Nonlinear field dependence of Hall effect and high-mobility multi-carrier transport in an altermagnet CrSb

As a promising candidate for altermagnet, CrSb possesses a distinctive compensated spin split band structure that could lead to groundbreaking concepts in the field of spintronics. In this work, we have grown high-quality CrSb single crystals and comprehensively investigated their electronic and magneto-transport properties. We have observed large, positive, and non-saturated magnetoresistance (MR) in CrSb, which obeys Kohler's rule, indicating its classic Lorentz scattering origins. The largest MR can reach 27% at 10 K and 9 T. Remarkably, a nonlinear magnetic field dependence of Hall effect resembling the spontaneous anomalous Hall is identified over a wide temperature range. It was found that the nonlinearity mainly stems from the incorporation of different carriers in the magnetoconductivity. According to the Fermi surface analyses of CrSb, we applied the three-carrier model to fit the conductivity data, yielding good agreement. The extracted carrier concentration ranges from 1018 to 1021 cm−3, with a high mobility up to ∼3 × 103 cm2/V s below 50 K. These indicate that CrSb behaves more like a semimetal. Furthermore, calculations using the semiclassical Boltzmann transport theory have reproduced the main features of the experimental MR and Hall effect in CrSb. These exceptional transport properties make CrSb unique for applications in spintronics as an altermagnet.