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arXiv 2202.09098cond-mat.supr-con
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超导体/铁磁绝缘体结构中的准粒子态密度和三重态关联

Quasiparticle density of states and triplet correlations in superconductor/ferromagnetic-insulator structures across a sharp domain wall

Alberto Hijano, Vitaly N. Golovach, F. Sebastián Bergeret

摘要:

已知铁磁绝缘体(FI)与超导体(S)接触会在FI/S界面处引起BCS态密度的自旋分裂。这种自旋分裂导致库珀对降低它们的单态相关性并获得奇频三重态相关性。我们考虑了一个在FI中具有尖锐磁畴壁的扩散FI/S双层膜,研究了局域准粒子态密度和三重态超导关联。在共线排列的域的情况下,我们通过求解Usadel方程得到解析结果。对于一个足够小的交换场或弱的超导性,我们还发现了任意的磁织构的解析表达式,这揭示了三重态分量矢量如何依赖于局部磁化的FI。对于磁化强度和交换场强度之间的任意角度,我们数值解决了尖锐畴壁的问题。最后,我们提出了两种不同的设置的基础上FI/S/F堆栈,其中F是一个铁磁层,过滤出单重态对,并通过隧道差分电导测量检测三重态相关的存在。

英文摘要:

A ferromagnetic insulator (FI) in contact with a superconductor (S) is known to induce a spin splitting of the BCS density of states at the FI/S interface. This spin splitting causes the Cooper pairs to reduce their singlet-state correlations and acquire odd-in-frequency triplet correlations. We consider a diffusive FI/S bilayer with a sharp magnetic domain wall in the FI and study the local quasiparticle density of states and triplet superconducting correlations. In the case of collinear alignment of the domains, we obtain analytical results by solving the Usadel equation. For a small enough exchange field or weak superconductivity, we also find an analytical expression for arbitrary magnetic textures, which reveals how the triplet component vector depends on the local magnetization of the FI. For an arbitrary angle between the magnetizations and the strength of the exchange field, we numerically solve the problem of a sharp domain wall. We finally propose two different setups based on FI/S/F stacks, where F is a ferromagnetic layer, to filter out singlet pairs and detect the presence of triplet correlations via tunneling differential conductance measurements.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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