Motivated by the recent discovery of superconductivity in La3Ni2O7 under high pressure, we explore its potential charge and spin instabilities through combined model analysis and first-principles calculations. Taking into account the small charge-transfer nature of high valence nickel, a fully correlated two-cluster model identifies a lattice-coupled charge instability characterized by substantial short-range fluctuations of oxygen holes. This instability is corroborated by density-functional-theory plus U calculations that also reveal a strong tendency towards concurrent antiferromagnetic ordering. The charge, spin, and associated lattice instabilities are significantly suppressed with increasing external pressure, contributing to the emergence of superconductivity in pressurized La3Ni2O7. Carrier doping is found to effectively suppress these instabilities, suggesting a viable strategy to stabilize a superconducting phase under ambient pressure.
@article{arxiv.2307.07154,
title = {Charge and spin instabilities in superconducting La$_3$Ni$_2$O$_7$},
author = {Xuejiao Chen and Peiheng Jiang and Jie Li and Zhicheng Zhong and Yi Lu},
journal= {arXiv preprint arXiv:2307.07154},
year = {2025}
}