Orbital-dependent electron correlation in double-layer nickelate La3Ni2O7

Jiangang Yang; Hualei Sun; Xunwu Hu; Yuyang Xie; Taimin Miao; Hailan Luo; Hao Chen; Bo Liang; Wenpei Zhu; Gexing Qu; Cui-Qun Chen; Mengwu Huo; Yaobo Huang; Shenjin Zhang; Fengfeng Zhang; Feng Yang; Zhimin Wang; Qinjun Peng; Hanqing Mao; Guodong Liu; Zuyan Xu; Tian Qian; Dao-Xin Yao; Meng Wang; Lin Zhao; X J Zhou

doi:10.1038/s41467-024-48701-7

Orbital-dependent electron correlation in double-layer nickelate La₃Ni₂O₇

Nat Commun. 2024 May 23;15(1):4373. doi: 10.1038/s41467-024-48701-7.

Authors

Jiangang Yang^#^{1

2}, Hualei Sun^#³, Xunwu Hu^#⁴, Yuyang Xie^{1

2}, Taimin Miao^{1

2}, Hailan Luo^{1

2}, Hao Chen^{1

2}, Bo Liang^{1

2}, Wenpei Zhu^{1

2}, Gexing Qu^{1

2}, Cui-Qun Chen⁴, Mengwu Huo⁴, Yaobo Huang⁵, Shenjin Zhang⁶, Fengfeng Zhang⁶, Feng Yang⁶, Zhimin Wang⁶, Qinjun Peng⁶, Hanqing Mao^{1

2

7}, Guodong Liu^{1

2

7}, Zuyan Xu⁶, Tian Qian¹, Dao-Xin Yao⁸, Meng Wang⁹, Lin Zhao^{10

11

12}, X J Zhou^{13

14

15}

Affiliations

¹ Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.
² School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China.
³ School of Science, Sun Yat-Sen University, Shenzhen, Guangdong, 518107, China.
⁴ Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices, School of Physics, Sun Yat-Sen University, Guangzhou, 510275, China.
⁵ Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, 201204, China.
⁶ Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.
⁷ Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China.
⁸ Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices, School of Physics, Sun Yat-Sen University, Guangzhou, 510275, China. yaodaox@mail.sysu.edu.cn.
⁹ Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices, School of Physics, Sun Yat-Sen University, Guangzhou, 510275, China. wangmeng5@mail.sysu.edu.cn.
¹⁰ Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China. LZhao@iphy.ac.cn.
¹¹ School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China. LZhao@iphy.ac.cn.
¹² Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China. LZhao@iphy.ac.cn.
¹³ Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China. XJZhou@iphy.ac.cn.
¹⁴ School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China. XJZhou@iphy.ac.cn.
¹⁵ Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China. XJZhou@iphy.ac.cn.

^# Contributed equally.

Abstract

The latest discovery of high temperature superconductivity near 80 K in La₃Ni₂O₇ under high pressure has attracted much attention. Many proposals are put forth to understand the origin of superconductivity. The determination of electronic structures is a prerequisite to establish theories to understand superconductivity in nickelates but is still lacking. Here we report our direct measurement of the electronic structures of La₃Ni₂O₇ by high-resolution angle-resolved photoemission spectroscopy. The Fermi surface and band structures of La₃Ni₂O₇ are observed and compared with the band structure calculations. Strong electron correlations are revealed which are orbital- and momentum-dependent. A flat band is formed from the Ni-3d $_{z^{2}}$ orbitals around the zone corner which is ~ 50 meV below the Fermi level and exhibits the strongest electron correlation. In many theoretical proposals, this band is expected to play the dominant role in generating superconductivity in La₃Ni₂O₇. Our observations provide key experimental information to understand the electronic structure and origin of high temperature superconductivity in La₃Ni₂O₇.