Krsnik Juraj, Held Karsten
Institute of Solid State Physics, TU Wien, 1040, Vienna, Austria.
Department for Research of Materials under Extreme Conditions, Institute of Physics, 10000, Zagreb, Croatia.
Nat Commun. 2025 Jan 2;16(1):255. doi: 10.1038/s41467-024-55465-7.
Waterfalls are anomalies in the angle-resolved photoemission spectrum where the energy-momentum dispersion is almost vertical, and the spectrum strongly smeared out. These anomalies are observed at relatively high energies, among others, in superconducting cuprates and nickelates. The prevalent understanding is that they originate from the coupling to some boson, with spin fluctuations and phonons being the usual suspects. Here, we show that waterfalls occur naturally in the process where a Hubbard band develops and splits off from the quasiparticle band. Our results for the Hubbard model with ab initio determined parameters well agree with waterfalls in cuprates and nickelates, providing a natural explanation for these spectral anomalies observed in correlated materials.
瀑布是角分辨光电子能谱中的异常现象，其能量-动量色散几乎是垂直的，且能谱强烈展宽。这些异常现象在相对较高的能量下被观测到，尤其在超导铜酸盐和镍酸盐中。普遍的理解是，它们源于与某种玻色子的耦合，自旋涨落和声子是常见的推测对象。在此，我们表明瀑布现象在哈伯德带从准粒子带发展并分裂出来的过程中自然出现。我们对具有从头算确定参数的哈伯德模型的结果与铜酸盐和镍酸盐中的瀑布现象吻合良好，为在关联材料中观测到的这些能谱异常提供了一种自然的解释。
