近日，北京高压科学研究中心上海分中心杨文革团队研究了高压低温条件下La₄Ni₃O_10-δ的晶体和电子结构。该研究于2025年11月18日发表在《美国化学会志》上。

近期在双层与三层鲁德斯伯里镍酸盐中发现压力诱导的高温超导现象，引发了全球对这些非常规超导体系的研究热潮。理解其晶体与电子结构对于揭示超导机制至关重要。对于三层结构的La₄Ni₃O_10-δ，目前结构研究仅局限于常温环境，其广阔的压强-温度相图仍有待探索。

研究组通过同步辐射X射线衍射（XRD）与X射线吸收谱（XAS）原位实验，在0-51.3 GPa压力区间与10-300 K温度范围内系统研究了La₄Ni₃O_10-δ的关键P-T相图。研究结果表明：La₄Ni₃O_10-δ在压力作用下经历从单斜晶系（P2₁/a空间群）到四方晶系（I4/mmm空间群）的相变，并在48 GPa以上压力环境下冷却时进一步转变为正交晶系（Bmab空间群），同时进入超导态。此外，镍的价态随压力增加而升高，并在低温下保持稳定。由于NiO₆八面体的畸变，镍的p、d轨道及其3d轨道与氧2p轨道间增强的杂化作用在超导态中扮演关键角色。该研究为揭示镍酸盐高温超导机制提供了重要见解，并为相关超导体系的深入研究奠定了基础。

附：英文原文

Title: Crystal and Electronic Structure Studies of La4Ni3O10δ under High-Pressure and Low-Temperature Conditions

Author: Nana Li, Jiayi Guan, Limin Yan, Xiaozhi Yan, Mingtao Li, Xuqiang Liu, Kai Zhang, Feiyu Li, Shu Cai, Haini Dong, Adama N-Diaye, Monica Amboage, Junjie Zhang, Yantao Cao, Hanjie Guo, Qingyu Kong, Liling Sun, Wenge Yang

Issue&Volume: November 18, 2025

Abstract: Recent discoveries of pressure-induced high-temperature superconductivity in bilayer and trilayer Ruddlesden–Popper nickelates have sparked global research interest in these unconventional superconducting systems. Understanding the crystal and electronic structures is essential to uncover the underlining mechanism of superconductivity. For trilayer La4Ni3O10δ, structural studies have only been conducted at ambient temperature, leaving a vast P–T space unexplored. Here we report our in situ investigations using X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS), covering pressures from 0 to 51.3 GPa and temperatures from 10 to 300 K, to explore the critical P–T phase diagram of La4Ni3O10δ. Our results show that La4Ni3O10δ undergoes a phase transition from monoclinic (P21/a) to tetragonal (I4/mmm) under pressure and is further transformed to an orthorhombic (Bmab) phase as it enters the superconducting state upon cooling at pressures above 48 GPa. Additionally, the Ni valence state increases with the pressure and remains stable at low temperatures. The p and d orbitals of Ni and the enhanced hybridization between Ni 3d and O 2p orbitals play a significant role in the superconducting state due to the distortion of the NiO6 octahedra. Our study provides important insights into the mechanisms driving high-Tc superconductivity in nickelates and establishes a basis for further investigation into related superconducting systems.

DOI: 10.1021/jacs.5c13966

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.5c13966