AI 中文总结
该研究在带有Rashba金属层的扩散型约瑟夫森结中，通过推导高次谐波自旋约瑟夫森电流的解析表达式，揭示了无需外部磁场即可产生自旋约瑟夫森二极管效应的机制。
AI 中文摘要
我们从理论上研究了带有Rashba金属层且处于铁磁交换场下的扩散型约瑟夫森结中的自旋约瑟夫森二极管效应（SJDE）。在准经典格林函数框架内，我们推导了一阶和二阶谐波自旋约瑟夫森电流的解析表达式。Rashba自旋轨道相互作用与交换场的相互作用会破坏反演对称性和时间反演对称性，在自旋电流-相位关系中产生额外的余弦项，并形成有限的φ₀相移。该相移会诱导正向与反向自旋电流之间的本征不对称性，从而在无需外部磁场的情况下产生SJDE。数值结果表明，由于二阶谐波分量被抑制，SJDE效率随金属厚度的增加而降低；而SJDE对自旋轨道相互作用强度的依赖关系则反映了相移增强与谐波抑制之间的竞争效应。这些发现表明，谐波分量之间的相互作用为非互易自旋输运提供了一种机制，且无需抑制自旋单重态关联。
英文摘要
We theoretically investigate the spin Josephson diode effect (SJDE) in a diffusive Josephson junction with a Rashba metal layer under a ferromagnetic exchange field. Within the quasiclassical Green's function framework, we derive analytical expressions for the first- and second-harmonic spin Josephson currents. The interplay between Rashba spin-orbit interaction and the exchange field breaks inversion and time-reversal symmetries, generating additional cosine terms in the spin current-phase relations and a finite phi0 phase shift. This phase shift induces an intrinsic asymmetry between forward and backward spin currents, leading to the SJDE without an external magnetic field. Numerical results show that the efficiency decreases with increasing metal thickness due to suppression of the second-harmonic component, while its dependence on spin-orbit interaction strength reflects competing effects between phase shift enhancement and harmonic suppression. These findings demonstrate that the interplay between harmonic components provides a mechanism for nonreciprocal spin transport without requiring suppression of spin-singlet correlations.
Comments17 pages, 8 figures
Journal refJ. Phys.: Condens. Matter 38, 315601 (2026)
