自旋轨道耦合莫特绝缘体中赝能隙、d波能隙及电子-玻色子耦合的电子结构研究

自旋轨道耦合莫特绝缘体是关联体系和自旋轨道耦合体系的交叉点所带来的前沿新兴领域。赝能隙、d波超导能隙和电子-玻色子耦合是铜氧化物高温超导体中的重要物理现象，且三者之间密切相关。近期，赝能隙、d波能隙和电子-玻色子耦合在电子掺杂自旋轨道耦合莫特绝缘体Sr2IrO4中相继被发现，进一步引起人们的兴趣。在自旋轨道耦合莫特绝缘体中系统的研究这三个物理现象，一方面可以和铜氧化合物进行比较，发现存在的普适性或差异性；另一方面可以探索强自旋轨道耦合对其带来的新影响和新现象。我们将结合已有研究基础，通过测量材料电子结构，对此项目展开研究：（1）在电子掺杂的Sr2IrO4中探索赝能隙、d波能隙的产生和起源，以及赝能隙、d波能隙、电子-玻色子耦合三者之间的相互关系; (2) 在空穴掺杂的Sr2IrO4中探索是否存在d波能隙及电子-玻色子耦合；（3）探索自旋轨道耦合对赝能隙、d波能隙及电子-玻色子耦合的影响。

Spin-orbit coupled Mott insulators represent a new frontier in condensed matter physics, where both correlations and spin-orbit coupling are at play. Pseudogap, d-wave superconducting gap and electron-boson coupling are three important and intertwined physical phenomena in cuprate high-temperature superconductors. Recently, much interest has been attracted by the observations of pseudogap, d-wave gap and electron-boson coupling in electron-doped spin-orbit coupled Mott insulator Sr2IrO4. The importance to study these three phenomena in spin-orbit coupled Mott insulators are two folds. First, by comparing the results with that in cuprates, one may establish the universality of some genuine physics in doped Mott insulators, or discover some differences between Sr2IrO4 and cuprates. Second, the strong spin-orbit coupling provides a unique opportunity to explore its impact on the above phenomena. Here, we propose to perform a systematic study on the pseudogap, d-wave gap and electron-boson coupling in spin-orbit coupled Mott insulators. ARPES measurements will be carried out to study the electronic structures of the materials. We will mainly focus on the following issues: (1) explore the origin and evolution of the pseudogap and d-wave gap in electron doped Sr2IrO4; understand the relationship between the pseudogap, d-wave gap and electron-boson coupling. (2) explore the possible existence of d-wave gap and electron-boson coupling in hole doped Sr2IrO4. (3) explore the possible impact on the pseudogap, d-wave gap and electron-boson coupling due to the (different strength of) spin-orbit coupling.