Possible enhancement of transition temperature due to magnetic impurities with internal structure in a superconductor

超导电性是科学技术进步的核心问题之一。我们研究了与高温超导体的稳定性条件有关的附加自由度，如轨道自由度与磁性自由度不同。在多带情况下，对于超导转变温度的提高，我们关注(1)超导带中序参数的相对符号和(2)与带电子耦合的多极(轨道矩)型磁性杂质。这一结果为超导和磁学的研究提供了一个新的概念。

Superconductivity is one of central issues in progress of science technology. We investigate additional degrees of freedom such as orbital that differ from magnetic degrees of freedom, which are relevant to stability conditions of higher temperature superconductors. In a multiband case, for increase of the transition temperature of superconductivity, we focus on(1) relative signs of order parameters in superconducting bands and(2) multipole(orbital moment) types of magnetic impurities coupled to band electrons. This result gives a new concept for the study of superconductivity and magnetism.