Lin Shi-Zeng
Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
J Phys Condens Matter. 2014 Dec 10;26(49):493202. doi: 10.1088/0953-8984/26/49/493202. Epub 2014 Nov 14.
This article reviews theoretical and experimental work on the novel physics in multiband superconductors. Multiband superconductors are characterized by multiple superconducting energy gaps in different bands with interaction between Cooper pairs in these bands. The discovery of prominent multiband superconductors MgB2 and later iron-based superconductors, has triggered enormous interest in multiband superconductors. The most recently discovered superconductors exhibit multiband features. The multiband superconductors possess novel properties that are not shared with their single-band counterpart. Examples include: the time-reversal symmetry broken state in multiband superconductors with frustrated interband couplings; the collective oscillation of number of Cooper pairs between different bands, known as the Leggett mode; and the phase soliton and fractional vortex, which are the main focus of this review. This review presents a survey of a wide range of theoretical exploratory and experimental investigations of novel physics in multiband superconductors. A vast amount of information derived from these studies is shown to highlight unusual and unique properties of multiband superconductors and to reveal the challenges and opportunities in the research on the multiband superconductivity.
本文综述了多带超导体中新型物理的理论和实验工作。多带超导体的特征是不同能带中存在多个超导能隙，且这些能带中的库珀对之间存在相互作用。显著的多带超导体MgB₂以及后来的铁基超导体的发现，引发了人们对多带超导体的巨大兴趣。最近发现的超导体都呈现出多带特征。多带超导体具有一些单带超导体所没有的新奇特性。例如：具有受挫带间耦合的多带超导体中的时间反演对称性破缺态；不同能带间库珀对数量的集体振荡，即所谓的莱格特模；以及相位孤子和分数涡旋，这些是本综述的主要关注点。本综述对多带超导体中新型物理的广泛理论探索和实验研究进行了概述。这些研究得出的大量信息凸显了多带超导体不同寻常和独特的性质，并揭示了多带超导研究中的挑战与机遇。
