Layered ferromagnet-superconductor structures: The π state and proximity effects
Layered ferromagnet-superconductor structures: The π state and proximity effects
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DOI：
10.1103/physrevb.69.014517
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发表时间：
2003-07
影响因子：
3.7
通讯作者：
Klaus Halterman;O. Valls
中科院分区：
文献类型：
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作者：
Klaus Halterman;O. Valls
我们通过数值解这些系统的自一致Bogoliubov-de Gennes方程，在低温下研究了SFS和SFSFS类型的清洁多层结构（其中S层本质上是超导的，F层是铁磁性的）。我们得到了对振幅的结果。局域态密度，局域磁矩。我们发现，作为分离相邻超导体的磁层厚度fd的函数，基态能量在两个稳定状态之间周期性地变化。第一种状态是普通的“0状态”，其中顺序参数在连续S层之间的相位差为零，第二种状态是“π状态”，其中符号交替，对应于相邻S层之间的相位差为π。这种行为可以通过简单的论证来理解。态密度和局部磁矩也反映了这种周期性。
We investigate clean mutilayered structures of the SFS and SFSFS type (where the S layer is intrinsically superconducting and the F layer is ferromagnetic), at low temperature, through numerical solution of the self-consistent Bogoliubov-de Gennes equations for these systems. We obtain results for the pair amplitude. the local density of states, and the local magnetic moment. We find that as a function of the thickness d F of the magnetic layers separating adjacent superconductors, the ground state energy varies periodically between two stable states. The first state is an ordinary "0 state," in which the order parameter has a phase difference of zero between consecutive S layers, and the second is a "π state," where the sign alternates, corresponding to a phase difference of π between adjacent S layers. This behavior can be understood from simple arguments. The density of states and the local magnetic moment also reflect this periodicity.