Novelli Fabio, Tollerud Jonathan O, Prabhakaran Dharmalingam, Davis Jeffrey A
Centre for Quantum and Optical Science, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia.
Department of Physical Chemistry II, Ruhr University Bochum, 44801 Bochum, Germany.
Sci Adv. 2020 Feb 28;6(9):eaaw9932. doi: 10.1126/sciadv.aaw9932. eCollection 2020 Feb.
Quantum materials displaying intriguing magnetic and electronic properties could be key to the development of future technologies. However, it is poorly understood how the macroscopic behavior emerges in complex materials with strong electronic correlations. While measurements of the dynamics of excited electronic populations have been able to give some insight, they have largely neglected the intricate dynamics of quantum coherence. Here, we apply multidimensional coherent spectroscopy to a prototypical cuprate and report unprecedented coherent dynamics persisting for ~500 fs, originating directly from the quantum superposition of optically excited states separated by 20 to 60 meV. These results reveal that the states in this energy range are correlated with the optically excited states at ~1.5 eV and point to nontrivial interactions between quantum many-body states on the different energy scales. In revealing these dynamics and correlations, we demonstrate that multidimensional coherent spectroscopy can interrogate complex quantum materials in unprecedented ways.
展现出有趣磁学和电学性质的量子材料可能是未来技术发展的关键。然而，对于具有强电子关联的复杂材料中宏观行为是如何出现的，人们了解甚少。虽然对激发电子群体动力学的测量能够提供一些见解，但它们在很大程度上忽略了量子相干的复杂动力学。在此，我们将多维相干光谱应用于一种典型的铜酸盐，并报告了持续约500飞秒的前所未有的相干动力学，这直接源于被20至60毫电子伏特隔开的光激发态的量子叠加。这些结果表明，该能量范围内的态与约1.5电子伏特处的光激发态相关，并指向不同能量尺度上量子多体态之间的非平凡相互作用。在揭示这些动力学和关联时，我们证明了多维相干光谱能够以前所未有的方式探究复杂量子材料。
