非常规超导体量子相干效应和新颖磁通态研究

Superconducting state is formed by the macroscopic phase coherence of large number of Copper pairs. The superconducting quantum coherence includes not only the phase coherence of the order parameter, which leads to many interesting phenomena, such as the Meissner effect, zero resistance state, flux quantization and Josephson effect, but also some unique quantum coherence state of quasiparticles (QPs), such as the in-gap states by the impurity scattering, the confined states within the vortex cores, etc. In this project we will investigate in some frontier directions concerning the superconducting quantum coherence. These cover the investigations on (1) The in-gap QPs states, the quasiparticle interference (QPI) and confined vortex states with several iron based superconductors with different Fermi surface topology. (2) Interface superconductivity by the topological insulator on multiband superconductors, the novel vortex core state and possible Majorana mode. (2) Vortex core structure and vortex lattice, dynamics of some new superconductors (Ta4Pd3Te16, K2Cr3As3, etc.) with low dimensionality. The project will shed light not only on the understanding of fundamental mechanism of unconventional superconductivity, but also the new comprehension on the vortices beyond the Abrikosov vortex in some newly discovered low dimensional superconductors.

超导态是电子库玻对形成宏观量子相干的结果。超导相干效应既包括超导序参量的相位相干所导致的一些有趣现象，如迈斯纳效应、零电阻现象、磁通量子化、约瑟夫森效应等，还包括准粒子的各种新奇量子相干态，如杂质散射诱导的隙间态，磁通芯内部的束缚态等等。本项目将围绕非常规超导体量子相干的一些前沿方向开展研究，重点关注（1）费米面构型不同的铁基超导体杂质散射形成的准粒子隙间态，准粒子相干散射，磁通涡旋芯态等，希望对铁基超导体的电子配对特性建立统一的图像； (2)在多带超导体上生长拓扑绝缘体并诱导界面超导，探寻其磁通芯态和可能的Majorana模；（3）研究一些新型低维非常规超导体(如Ta4Pd3Te16, K2Cr3As3等)的新颖磁通态物理，期望获得超越对Abrikosov磁通态的理解。本项目涉及受限和关联体系，不仅能促进对非常规超导机理这个重大科学问题的认识，还对新颖磁通态性质进行研究。

经过项目组成员的通力合作，我们在非常规超导体量子相干的一些前沿方向取得重要进展，如统一铁基超导配对机理方面的工作、构造新的拓扑超导材料平台和对其性质的研究以及对新颖磁通态和磁通物理的研究等，完成了项目实施的既定目标。在项目的资助下共发表SCI收录论文55篇，Nature子刊文章6篇（均为通讯作者），PRL/PRX文章3篇（通讯作者1篇），Science Advances文章2篇（均为通讯作者），Nano Letters文章 1篇（通讯作者），在PRB等影响因子超过3的杂志上发表论文30篇（通讯作者23篇），获得国际会议邀请报告27个，毕业研究生20名。