The discovery of superconductivity in infinite-layer nickelates brings us tantalizingly close to a material class that mirrors the cuprate superconductors. We measured the magnetic excitations in these nickelates using resonant inelastic x-ray scattering at the Ni L₃-edge. Undoped NdNiO₂ possesses a branch of dispersive excitations with a bandwidth of approximately 200 milli–electron volts, which is reminiscent of the spin wave of strongly coupled, antiferromagnetically aligned spins on a square lattice. The substantial damping of these modes indicates the importance of coupling to rare-earth itinerant electrons. Upon doping, the spectral weight and energy decrease slightly, whereas the modes become overdamped. Our results highlight the role of Mottness in infinite-layer nickelates.

无限层镍酸盐超导性的发现使我们非常接近反映铜酸盐超导体的材料类别。我们在 Ni L ₃边缘使用共振非弹性 X 射线散射测量了这些镍酸盐中的磁激发。未掺杂的 NdNiO ₂拥有一个带宽约为 200 毫电子伏特的色散激发分支，这让人联想到方形晶格上强耦合、反铁磁排列的自旋波。这些模式的显着阻尼表明耦合到稀土流动电子的重要性。掺杂后，光谱权重和能量略有下降，而模式变得过阻尼。我们的结果突出了 Mottness 在无限层镍酸盐中的作用。