Tunneling Magnetoresistance Effect in Altermagnetic Tunnel Junctions with g-wave splitting

Altermagnets, a class of unconventional antiferromagnets with non-relativistic spin-splitting, offer promising potential for antiferromagnetic spintronic devices. While many altermagnets are limited by either low magnetic transition temperatures or weak spin splitting, the recently discovered metal CrSb, with high Néel temperature (T_N = 710 K) and significant spin-splitting due to its unique spin space group, provides a robust platform for remarkable tunneling magnetoresistance (TMR) in collinear all-antiferromagnetic tunnel junctions (AATJs). This study systematically investigates the spin-polarized Fermi surface of CrSb and spin-dependent electron transport in CrSb-based AATJs. The CrSb/β-InSe/CrSb junction with a 3L InSe barrier exhibits a TMR ratio of approximately 290%, with energy-dependent analysis revealing TMR ratios that may exceed 850% when considering the shift of the Fermi energy. We also demonstrate the angle-dependent TMR of CrSb-based AATJs by adjusting Néel vector orientations. Our findings might provide strong theoretical support for CrSb as a versatile building block for all-antiferromagnetic memory devices.