Spin-transfer torques in antiferromagnetic textures: Efficiency and quantification method
Spin-transfer torques in antiferromagnetic textures: Efficiency and quantification method
复制标题
反铁磁织构中的自旋转移矩：效率和量化方法
DOI：
10.1103/physrevb.94.054409
复制
发表时间：
2016
期刊：
影响因子：
--
通讯作者：
Jun'ichi Ieda,Jairo Sinova
中科院分区：
文献类型：
--
作者：
Yuta Yamane;Jun'ichi Ieda,Jairo Sinova
我们建立了织构反铁磁体的自旋转移力矩理论，它涵盖了交换耦合能相对于子晶格间电子动力学动能的小到大的限制。我们的理论给出了反铁磁体中自旋转移力矩效率的自然定义，用定义明确的材料参数表示，揭示了电荷电流主要与反铁磁序参数和次晶格倾斜力矩耦合，在大交换耦合和小交换耦合的极限下。通过分析存在电荷电流时的反铁磁自旋波频散，可以量化这种影响：在大交换耦合极限下，自旋波多普勒移总是发生的，而在相反的极限下，唯一对电荷电流起反应的自旋波模是那些携带明显的次晶格倾斜矩的模。这些发现为理解和设计属于不同亚晶格结构的反铁磁体中的自旋转移力矩提供了一个框架，例如，二体反铁磁体和层状反铁磁体。
We formulate a theory of spin-transfer torques in textured antiferromagnets, which covers the small to large limits of the exchange coupling energy relative to the kinetic energy of the intersublattice electron dynamics. Our theory suggests a natural definition of the efficiency of spin-transfer torques in antiferromagnets in terms of well-defined material parameters, revealing that the charge current couples predominantly to the antiferromagnetic order parameter and the sublattice-canting moment in, respectively, the limits of large and small exchange coupling. The effects can be quantified by analyzing the antiferromagnetic spin-wave dispersions in the presence of charge current: in the limit of large exchange coupling the spin-wave Doppler shift always occurs, whereas, in the opposite limit, the only spin-wave modes to react to the charge current are ones that carry a pronounced sublattice-canting moment. The findings offer a framework for understanding and designing spin-transfer torques in antiferromagnets belonging to different classes of sublattice structures such as, e.g., bipartite and layered antiferromagnets.