Electronic Correlation and Pseudogap-Like Behavior of High-Temperature Superconductor La<sub>3</sub>Ni<sub>2</sub>O<sub>7</sub>
Yidian 义典 Li 李, Xian 宪 Du 杜, Yantao 延涛 Cao 曹, Cuiying 翠颖 Pei 裴, Mingxin 明鑫 Zhang 张, Wenxuan 文轩 Zhao 赵, Kaiyi 恺熠 Zhai 翟, Runzhe 润哲 Xu 许, Zhongkai 仲楷 Liu 柳, Zhiwei 志伟 Li 李, Jinkui 金奎 Zhao 赵, Gang 刚 Li 李, Yanpeng 彦鹏 Qi 齐, Hanjie 汉杰 Guo 郭, Yulin 宇林 Chen 陈, Lexian 乐仙 Yang 杨
Abstract
Abstract High-temperature superconductivity (HTSC) remains one of the most challenging and fascinating mysteries in condensed matter physics. Recently, superconductivity with transition temperature exceeding liquid-nitrogen temperature is discovered in La 3 Ni 2 O 7 at high pressure, which provides a new platform to explore the unconventional HTSC. In this work, using high-resolution angle-resolved photoemission spectroscopy and ab initio calculation, we systematically investigate the electronic structures of La 3 Ni 2 O 7 at ambient pressure. Our experiments are in nice agreement with ab initio calculations after considering an orbital-dependent band renormalization effect. The strong electron correlation effect pushes a flat band of d z 2 orbital component below the Fermi level ( E F ), which is predicted to locate right at E F under high pressure. Moreover, the d x 2 – y 2 band shows pseudogap-like behavior with suppressed spectral weight and diminished quasiparticle peak near E F . Our findings provide important insights into the electronic structure of La 3 Ni 2 O 7 , which will shed light on understanding of the unconventional superconductivity in nickelates.