Resolving the electronic ground state of La3Ni2O7-δ films

• DOI: 10.1038/s42005-025-01971-z
• Publication Date: 2025-02-03T14:44:56Z
• Authors: Xiaolin Ren; Ronny Sutarto; Xianxin Wu; Jianfeng Zhang; Hai Huang; Tao Xiang; Jiangping Hu; Riccardo Comin; Xingjiang Zhou; Zhihai Zhu
• Keywords: QB460-466; Superconductivity (cond-mat.supr-con); Condensed Matter - Materials Science; Condensed Matter - Strongly Correlated Electrons; Strongly Correlated Electrons (cond-mat.str-el); Physics; QC1-999; Condensed Matter - Superconductivity; Materials Science (cond-mat.mtrl-sci); FOS: Physical sciences; Astrophysics

The recent discovery of a superconductivity signature in La3Ni2O7-δ under pressure 14 GPa, with superconducting transition temperature around 80 K, has attracted considerable attention. An important aspect investigating electronic structures is discerning the extent to which ground state resembles parent cuprate superconductor, charge transfer insulator long-range antiferromagnetism. Through X-ray absorption spectroscopy, we reveal influence oxygen ligands on states Ni ions, displaying nature akin but distinct orbital configurations. Additionally, films, detect superlattice reflection (1/4, 1/4, L) at L edge using resonant scattering measurements. Further examination resonance profile indicates that originates from d orbitals. By evaluating reflection's azimuthal angle dependence, confirm presence collinear antiferromagnetic spin ordering and charge-like anisotropy ordered same periodicity. Our findings microscopic relationship between these two components dependence intensity reflection. This investigation enriches our understanding high-temperature high pressure. bilayer nickelates offers new material platform explore superconductivity. In this study, authors identify La3Ni2O7 film ambient revealing critical role ligand existence along anisotropy.