Abstract：The newly discovered superconductivity in hole doped infinite-layer nickelates (IL-N) have attracted extensive investigation. Motivated by the recent X-ray absorption spectroscopy (XAS) and resonant inelastic x-ray scattering (RIXS) experiments, based on Ni impurity calculations, we explored the nature of the parent compound and hole doped states of IL-N by including the crystal field splitting, the Ni-3d8 multiplet structure, and the hybridization between Ni-3d orbitals and the Nd-5d orbitals that are formally replaced with a totally symmetric orbital Zs based band centered at the missing O in the Nd layer.

For the parent compound, we showed that the spectrum of Ni-3d9Zs2 state spreads over a large energy range and cannot be represented by a single orbital energy as suggested in other calculations, which is qualitatively consistent with the RIXS measurements showing a broad distribution of the Ni-3d9z2 hole state. For the hole-doped systems, we showed that adding these additional ingredients can still result in the lowest-energy hole-doped state having a singlet character.

主讲人简介：蒋密，苏州大学教授，2014年于美国加州大学戴维斯分校获得博士学位，2014-2020年在瑞士ETH和加拿大UBC从事博士后研究工作，2021年加入苏州大学物理科学与技术学院。研究方向为计算凝聚态物理：针对各类强关联电子体系，如非常规超导体，重费米子材料等的理论和计算研究。近期研究方向侧重于新近发现的镍基超导体系和重费米子体系。