高级检索

非对称自旋力矩:反铁磁奈尔矢量调控的新图像

Asymmetric spin torque:a new picture for Néel vector control in antiferromagnets

  • 摘要: 反铁磁体因零净磁矩、无杂散场和太赫兹量级动力学,被认为是新一代自旋电子器件的重要候选体系。利用自旋力矩实现反铁磁体序参量——奈尔矢量的确定性调控,是反铁磁器件完成信息写入的关键。然而,对于共线反铁磁体,长期缺少一种既不依赖特殊对称性、又适用于真实器件结构的奈尔矢量调控图像。文章介绍了近年来研究者逐渐认识到的一个关键问题:传统基于“完全相同”或“严格相反”两类自旋积累极限的自旋力矩图像,难以刻画真实反铁磁器件中的写入过程。由于异质结界面、子晶格堆叠和体相对称性破缺等因素,两个子晶格在截获注入自旋时通常并不等价,并由此产生“非对称自旋力矩”。这一机制并未改变自旋力矩作为角动量交换过程的物理本质,却揭示了这种交换在真实反铁磁器件中如何通过子晶格的局域不等价响应得以实现,并由此决定奈尔矢量的演化路径与最终状态。非对称自旋力矩不仅为反铁磁奈尔矢量调控提供了一种新的物理图像,也为理解和实现真实反铁磁器件中的高效、精确写入提供了理论基础。

     

    Abstract: Antiferromagnets are promising candidates for next-generation spintronic devices because of their zero net magnetization, vanishing stray fields, and terahertz-scale dynamics. Deterministic control of the Néel vector by spin torque is crucial for electrical writing in antiferromagnetic devices. For collinear antiferromagnets, however, the conventional spin torque picture based on two idealized limits of spin accumulation—perfectly uniform or strictly staggered—does not adequately describe the writing process in realistic device structures. In practice, interface effects, sublattice stacking, and symmetry breaking often make spin accumulation on the two sublattices unequal, giving rise to an asymmetric spin torque. This mechanism reveals how angular momentum transfer occurs in realistic antiferromagnetic devices through locally inequivalent sublattice responses, thereby determining the dynamical trajectory and final state of the Néel vector. Asymmetric spin torque thus provides a new physical picture for Néel vector control and a useful framework for understanding and achieving efficient, deterministic writing in realistic antiferromagnetic devices.

     

/

返回文章
返回