时间：12月24日（周三）上午9：30

地点：勤园 20-518

报告简介：

  The discovery of superconductivity in nickelates has drawn great attention. In this talk, We present our ab initio many-body studies on infinite-layer nickelates RNiO2 (R is a rare earth element) and Ruddlesden-Popper phase nickelate La3Ni2O7. 1) For infinite-layer nickelates, we identify the existence of a low-energy interstitial-s orbital [1] and reveal its critical role on charge order [2], Fermi surface [3], and superconductivity [4]. 2) For Ruddlesden-Popper nickelate La3Ni2O7, we show that the pairing symmetry of this superconductor sensitively depends on the crystal field splitting of Ni-eg orbitals, suggesting a possible switch of the pairing symmetry from d-wave to s-wave via epitaxial strain [5]. Our work highlights the multi-orbital nature of nickelate superconductors, which leads to physical properties distinct from cuprate superconductors.

Reference:

[1] Yuhao Gu, Sichen Zhu, Xiaoxuan Wang, Jiangping Hu, Hanghui Chen^*, “A substantial hybridization between correlated Ni-d orbital and itinerant electrons in infinite-layer nickelates”, Communications Physics 3, 84 (2020).

[2] Hanghui Chen^*, Yi-feng Yang^*, Guang-Ming Zhang^* and Hongquan Liu, “An electronic origin of charge order in infinite-layer nickelates”, Nature Communications 14, 5477 (2023).

[3] Wenjie Sun, Zhicheng Jiang, Chengliang Xia, Bo Hao, Yueying Li, Shengjun Yan, Maosen Wang, Hongquan Liu, Jianyang Ding, Jiayu Liu, Zhengtai Liu, Jishan Liu, Hanghui Chen^*, Dawei Shen^*, Yuefeng Nie^*, “Electronic Structure of Superconducting Infinite-Layer Lanthanum Nickelates”, Science Advances 11, eadr5116 (2025).

[4] Chengliang Xia, Shengjie Zhou, Hanghui Chen^*, "Three-Dimensional Fermi Surface, Van Hove Singularity and Enhancement of Superconductivity in Infinite-Layer Nickelates", arXiv:2504.18778 (2025).

[5] Hongquan Liu, Chengliang Xia, Shengjie Zhou, Hanghui Chen^*, “Sensitive dependence of pairing symmetry on Ni-e_g crystal field splitting in the nickelate superconductor La₃Ni₂O₇”, Nature Communications 16, 1054 (2025).

报告人简介：

  Hanghui Chen is an Associate Professor of Physics at NYU Shanghai and a Global Network Associate Professor in the Department of Physics at NYU. Prior to joining NYU Shanghai, he was a post-doctoral fellow at Columbia University. He holds a PhD in physics from Yale University and a BS in physics from Peking University. Professor Chen’s research interests lie at the intersection of condensed matter physics and materials science. He combines state-of-the-art first principles and many-body model calculations to study strongly correlated properties of quantum materials, with an emphasis on unconventional superconductivity.