Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
Phys Rev Lett. 2012 Nov 30;109(22):227003. doi: 10.1103/PhysRevLett.109.227003. Epub 2012 Nov 27.
We suggest a mechanism which promotes the existence of a phase soliton--a topological defect formed in the relative phase of superconducting gaps of a two-band superconductor with s(+-) type of pairing. This mechanism exploits the proximity effect with a conventional s-wave superconductor which favors the alignment of the phases of the two-band superconductor which, in the case of s(+-) pairing, are π shifted in the absence of proximity. In the case of a strong proximity such an effect can be used to reduce the soliton's energy below the energy of a soliton-free state, thus making the soliton thermodynamically stable. Based on this observation we consider an experimental setup, applicable for both stable and metastable solitons, which can be used to distinguish between ss(+-) and s(++) types of pairing in the iron-based multiband superconductors.
我们提出了一个机制，该机制促进了相孤子的存在——在具有 s(+-)型配对的双带超导体的超导能隙的相对相位中形成的拓扑缺陷。该机制利用了与传统 s 波超导体的近邻效应，有利于双带超导体的相位对齐，在不存在近邻效应的情况下，s(+-)配对的相位相差 π。在近邻效应较强的情况下，这种效应可以用来降低孤子的能量，使其低于无孤子状态的能量，从而使孤子在热力学上稳定。基于这一观察，我们考虑了一种实验设置，适用于稳定和亚稳定孤子，可以用来区分铁基多带超导体中的 ss(+-)和 s(++)型配对。
