Xu Shuxiang, Wang Hao, Huo Mengwu, Hu Deyuan, Wu Qiong, Yue Li, Wu Dong, Wang Meng, Dong Tao, Wang Nanlin
International Center for Quantum Materials, School of Physics, Peking University, Beijing, China.
Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices, School of Physics, Sun Yat-Sen University, Guangzhou, Guangdong, China.
Nat Commun. 2025 Jul 31;16(1):7039. doi: 10.1038/s41467-025-62294-9.
Recent discoveries of superconductivity in Ruddlesden-Popper nickelates realize a rare category of superconductors. However, the use of high-pressure diamond anvil cells limits spectroscopic characterization of the density waves and superconducting gaps. Here, we systematically studied the pressure evolution of LaNiO using ultrafast optical pump-probe spectroscopy. We found that the transition temperature and energy gap of density waves are suppressed with increasing pressure and disappear suddenly near 17 GPa where structural transition appears. In addition, the observation of a single density wave gap indicates that the spin density wave and charge density wave remain coupled as pressure increases, rather than decoupling. After the density wave collapse, a distinct low-temperature regime emerges, characterized by a small gap consistent with potential superconducting pairing. The separated phase region of superconductivity and density waves suggests that superconductivity in pressurized-LaNiO competes strongly with density waves, offering new insights into the interplay between these two phenomena.
最近在鲁德尔斯登-波珀镍酸盐中发现的超导现象实现了一类罕见的超导体。然而，高压金刚石砧盒的使用限制了对密度波和超导能隙的光谱表征。在此，我们使用超快光泵浦-探测光谱系统地研究了LaNiO的压力演化。我们发现，密度波的转变温度和能隙随着压力的增加而受到抑制，并在出现结构转变的17 GPa附近突然消失。此外，对单一密度波能隙的观测表明，随着压力增加，自旋密度波和电荷密度波保持耦合，而非解耦。在密度波崩塌后，出现了一个独特的低温区域，其特征是与潜在超导配对相一致的小能隙。超导和密度波的分离相区表明，加压LaNiO中的超导与密度波强烈竞争，为这两种现象之间的相互作用提供了新的见解。
