Deterministic Switching of the Néel Vector by Asymmetric Spin Torque

Shui-Sen Zhang, Zi-An Wang, Bo Li, Wen-Jian Lu, Mingliang Tian, Yu-Ping Sun, Haifeng Du, Ding-Fu Shao

Published: 2025/6/12

Abstract

N\'{e}el vector, the order parameter of collinear antiferromagnets, serves as a state variable in associated antiferromagnetic (AFM) spintronic devices to encode information. A deterministic switching of N\'{e}el vector is crucial for the write-in operation, which, however, remains a challenging problem in AFM spintronics. Here we demonstrate, based on analytical derivation and macro-spin simulations, that N\'{e}el vector switching can be generally achieved via a current-induced spin torque, provided the spin accumulations responsible for this torque are non-identical between opposite sublattices. This condition occurs widely in AFM films, as symmetry equivalence between sublattice-dependent spin accumulations is usually absent, allowing unequal spin accumulations induced by Edelstein effect or a spin current. Unlike previously studied spin torques induced by uniform or staggered spin accumulations -- where either the field-like or damping-like component dominates exclusively -- the asymmetric spin torque features cooperative contributions from both components, leading to N\'{e}el vector dynamics that are fundamentally distinct from previous expectations. The switching conditions derived analytically agree well with simulation results and suggest various directions for further optimization. Our work establishes a general mechanism for current-induced N\'{e}el vector switching, which is in principle feasible for all collinear antiferromagnets, and thus paves the route to realize efficient writing in antiferromagnetic spintronics.

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