时间：5月25日（周一）上午10：00

地点：勤园20-518

报告简介：

The high-temperature superconductivity discovered recently in the Ruddlesden-Popper (RP) phase multilayer superconductors has aroused great research interests. In this talk, I will first make a brief introduction over the experimental progress, and then report our series of works adopting the strong-coupling picture for this family. We propose that the SC of La3Ni2O7 under high pressure is carried by the d_{x^2-y^2} orbital, and that the d_{z^2} orbital also plays an important role through the Hund’s rule coupling. Based on this viewpoint, we construct the d_{x^2-y^2} orbital bilayer t-J-J_{\perp} model for La3Ni2O7. With this model, we can naturally understand why HTSC arises under HP or in the film at AP. Recently, using this model, we provide a unified understanding toward the experiments which control Tc through tuning enviroment conditions, establishing this model as the minimal model regarding the pairing mechanism in the bilayer nickelates. We also predict possible ways to enhance the Tc, with part of them verified by experiments.

报告人简介：

杨帆，北京理工大学换妻 教授。2002年博士毕业于北京大学换妻 ，2004年从清华大学高等研究中心博后出站，之后加入北京理工大学换妻 。2013年被聘为教授。杨帆的主要研究方向为强关联和超导理论。曾长期在铜基超导、量子自旋液体和铁基超导领域展开研究。近期的研究兴趣集中在镍基超导、准晶电子态和转角石墨烯等领域。发表论文100余篇，被引4000余次。其工作在镍基超导机理探索方面取得系统性进展，提出双层镍酸盐中电子关联与晶格畸变协同调控超导配对的新图像，为理解非常规超导的普适机制提供了关键理论支撑。