Spin transfer torque induced deterministic Néel vector switching in altermagnets
Phys. Rev. B 113, 224444 – Published 25 June, 2026
DOI: https://doi.org/10.1103/8qhx-rwww
Abstract
The process of spin-transfer torque in an altermagnet (AM) is theoretically investigated from the perspective of disparate effective exchange fields acting on the two sublattices. The momentum dependent, anisotropic spin splitting in the AM band structure can cause this asymmetry, leading ultimately to a net uncompensated torque to the Néel vector through preferential absorption of injected electron spins by one of the sublattices. A theoretical model based on this skewed electron spin angular momentum transfer to sublattice magnetizations is developed to account for the effect phenomenologically in the Néel vector dynamics. A subsequent analysis clearly illustrates that a spin-polarized current injection can induce the Néel vector motion in an AM closely resembling that of the magnetization in a ferromagnet under spin-transfer torque. Numerical calculations in a magnetic tunnel junction geometry establish the conditions for a range of responses including deterministic switching and self-oscillations in terms of the injected spin-polarized current density and characteristic material properties. Clearly, the order parameter in an AM with sufficiently strong spin-dependent anisotropy can be modulated effectively via electrical control just as in a ferromagnet, while retaining at the same time advantages attributed to antiferromagnetic dynamics.
