Ultrafast manipulation of the Néel vector in metallic antiferromagnets most commonly occurs by generation of spin-orbit (SOT) or spin-transfer (STT) torques. Here, we predict another possibility for antiferromagnetic domain switching by using novel laser optical torques (LOTs). We present results of atomistic spin dynamics simulations from the application of LOTs for all-optical switching of the Néel vector in the antiferromagnet Mn₂Au. The driving mechanism takes advantage of the sizeable exchange enhancement, characteristic of antiferromagnetic dynamics, allowing for picosecond 90 and 180-degree precessional toggle switching of the Néel vector with laser fluences on the order of mJ/cm². A special symmetry of these novel torques greatly minimises the over-shooting effect common to precessional spin switching by SOT and STT methods. We demonstrate the opportunity for LOTs to produce deterministic, non-toggle switching of single antiferromagnetic domains. Lastly, we show that even with sizeable ultrafast heating by laser in metallic systems, there exist a large interval of laser parameters where the LOT-assisted toggle and preferential switchings in magnetic grains have probabilities close to one. The proposed protocol could be used on its own for all-optical control of antiferromagnets for computing or memory storage, or in combination with other switching methods to lower energy barriers and/or to prevent over-shooting of the Néel vector.

金属反铁磁体中 Néel 矢量的超快操作最常见的是通过产生自旋轨道 （SOT） 或自旋转移 （STT） 扭矩来实现的。在这里，我们通过使用新型激光光扭矩 （LOT） 预测了反铁磁域切换的另一种可能性。我们介绍了原子自旋动力学模拟的结果，这些结果来自将 LOT 应用于反铁磁体 Mn₂Au 中 Néel 矢量的全光切换。驱动机构利用了反铁磁动力学特性的相当大的交换增强，允许 Néel 矢量的皮秒 90 度和 180 度进动切换，激光通量约为^mJ/cm 2。这些新扭矩的特殊对称性大大减少了通过 SOT 和 STT 方法进行的岁差自旋切换常见的过冲效应。我们展示了 LOT 产生单个反铁磁域的确定性、非切换开关的机会。最后，我们表明，即使在金属系统中通过激光进行相当大的超快加热，也存在较大的激光参数区间，其中磁性晶粒中的 LOT 辅助切换和优先开关的概率接近 1。所提出的协议可以单独用于计算或内存存储的反铁磁体的全光学控制，或与其他开关方法结合使用，以降低能量势垒和/或防止 Néel 矢量的过冲。