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Spontaneous spin current near the interface between ferromagnets and unconventional superconductors

Kazuhiro Kuboki·Hidenori Takahashi
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Abstract

Proximity effects between ferromagnets (F) and superconductors (S) with broken time-reversal symmetry (T) are studied theoretically. For the S side we consider a chiral (p_x \pm ip_y)-wave, and a d_{x^2-y^2}-wave superconductor, the latter of which can form T-breaking surface state, i.e., (d_{x^2-y^2} \pm is)-state. The Bogoliubov de Gennes equation which describes the spatial variations of the superconducting order parameter and the magnetization is derived and solved numerically. It is found that a spontaneous spin current flows along the interface between the (p_x \pm ip_y)-wave superconductor and the ferromagnet. On the contrary, in the case of a [110] interface of the d_{x^2-y^2}-wave SC, the surface state has a (d \pm p_x \pm p_y)-wave (or (d_{x^2-y^2} \pm is)-wave) symmetry, and thus no (only charge) spontaneous current arises.

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Kazuhiro Kuboki, Hidenori Takahashi. 2002-10-10. Spontaneous spin current near the interface between ferromagnets and unconventional superconductors. https://doi.org/10.1016/s0921-4526(02)02367-0

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