Symmetries of Pairing Correlations in Superconductor¨CFerromagnet Nanostructures

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• 作者：M. Eschrig ; T. L?fwander ; T. Champel ; J. C. Cuevas ; J. Kopu and Gerd Sch?n
• 关键词：Pacs Numbers 74.45.+c ; 74.20.Rp ; 74.50.+r
• 刊名：Journal of Low Temperature Physics
• 出版年：2007
• 出版时间：May, 2007
• 年：2007
• 卷：147
• 期：3-4
• 页码：457-476
• 全文大小：234 KB

文摘

Using selection rules imposed by the Pauli principle, we classify pairing correlations according to their symmetry properties with respect to spin, momentum, and energy. We observe that inhomogeneity always leads to mixing of even- and odd-energy pairing components. We investigate the superconducting pairing correlations present near interfaces between superconductors and ferromagnets, with focus on clean systems consisting of singlet superconductors and either weak or half-metallic ferromagnets. Spin-active scattering in the interface region induces all of the possible symmetry components. In particular, the long-range equal-spin pairing correlations have odd-frequency s-wave and even-frequency p-wave components of comparable magnitudes. We also analyze the Josephson current through a half-metal. We find analytic expressions and a universality in the temperature dependence of the critical current in the tunneling limit.