Ferromagnetic features of zero-bias conductance peaks in a ferromagnet/insulator/superconductor junction
Ferromagnetic features of zero-bias conductance peaks in a ferromagnet/insulator/superconductor junction
复制标题
铁磁体/绝缘体/超导体结中零偏置电导峰值的铁磁特征
DOI：
10.1088/0953-8984/24/36/365702
复制
发表时间：
2012
期刊：
影响因子：
--
通讯作者：
M. Yamashiro
中科院分区：
文献类型：
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作者：
N. Yoshida;M. Yamashiro
在超导态具有相反自旋对对称的情况下，给出了弹道铁磁/铁磁绝缘体/超导体结隧穿电导率的一般公式。该公式正确地表明，铁磁性是由上下自旋电子之间的有效质量差引起的。本文采用了有效质量不匹配铁磁体和标准斯通纳铁磁体。作为该公式的应用，我们研究了包括自旋三重态p波超导体在内的结的隧道效应，其中我们选择了普通绝缘体作为绝缘区域，尽管我们的公式可以用于铁磁绝缘体。然后，我们可以把注意力集中在铁磁性金属的特征上。根据电导归一化的方法，两种铁磁体的电导谱显示出明显的差异。特别是，在零偏导峰中可以看到本质上的差异，这反映了每种铁磁体的特性。从得到的结果来看，我们认为在结处隧道电导的测量为我们提供了关于金属中流动铁磁性机制的有用信息。
We present a general formula for tunneling conductance in ballistic ferromagnet/ferromagnetic insulator/superconductor junctions where the superconducting state has the opposite spin pairing symmetry. The formula shows, correctly, that ferromagnetism has been induced by the effective mass difference between up- and down-spin electrons. This effectively mass mismatched ferromagnet and a standard Stoner ferromagnet have been employed in this paper. As an application of the formulation, we have studied the tunneling effect for junctions including a spin-triplet p-wave superconductor, where we choose a normal insulator for the insulating region, although our formula can be used for a ferromagnetic insulator. Then, we have been able to devote our attention to features of a ferromagnetic metal. The conductance spectra show a clear difference between the two ferromagnets depending upon the method of normalization of the conductance. In particular, an essential difference is seen in the zero-bias conductance peaks, reflecting the characteristics of each ferromagnet. From the obtained results, we suggest that the measurements of the tunneling conductance in the junction provide us with useful information about the mechanism of itinerant ferromagnetism in metals.