Evolution of Charge-Lattice Dynamics across the Kuramoto Synchronization Phase Diagram of Quantum Tunneling Polarons in Cuprate Superconductors
Evolution of Charge-Lattice Dynamics across the Kuramoto Synchronization Phase Diagram of Quantum Tunneling Polarons in Cuprate Superconductors
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DOI：
10.3390/condmat6040052
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发表时间：
2021-12
期刊：
影响因子：
1.7
通讯作者：
Victor Velasco;M. B. Silva Neto;A. Perali;S. Wimberger;A. Bishop;S. Conradson
中科院分区：
文献类型：
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作者：
Victor Velasco;M. B. Silva Neto;A. Perali;S. Wimberger;A. Bishop;S. Conradson
由于扩展X射线吸收精细结构（EXAFS）对瞬时结构因子S（Q，t = 0）的敏感性，它是研究电荷和晶格动力学耦合的凝聚态系统动力学结构的有力工具。当应用于空穴掺杂铜氧化物超导体时，EXAFS揭示了内部量子隧穿极化子（IQTP）的存在。一个IQTP出现在EXAFS作为一个两个网站的某些Cu-O对的分布，这也是重复的非弹性散射，但没有观察到在标准的衍射测量。已经发现Cu-Sr对分布是高度非谐的，并且与IQTP和超导性两者强烈相关，例如在YSr2Cu2.75Mo0.25O7.54（Tc=84 K）中。为了描述这样的非平凡的，非谐的电荷晶格动力学，我们提出了一个模型哈密顿的原型六原子团簇，其中两个铜顶端-O IQTP是通过Cu原子的电荷转移桥由一个O原子在CuO 2平面和非谐耦合通过Sr原子。通过应用一个精确的对角化程序，这个集群，我们已经验证了我们的模型确实产生了一个复杂的相互作用之间的电荷和晶格动力学。然后，通过使用仓本模型的耦合量子振荡器的同步，我们已经发现了一个一阶相变的IQTP同步，锁相相位。最重要的是，我们已经表明，这种转变的结果，特别是从非谐性。最后，我们提供了一个相图，显示了在我们的模型中作为电荷晶格和非谐耦合的函数的IQTP的相位锁定的发病。我们已经发现，电荷，最初仅限于顶端的氧，部分泵入CuO 2平面中的同步相，这表明在掺杂的铜酸盐的同步动态结构和高温超导性（HTSC）之间的可能的连接。
Because of its sensitivity to the instantaneous structure factor, S(Q,t = 0), Extended X-ray Absorption Fine Structure (EXAFS) is a powerful tool for probing the dynamic structure of condensed matter systems in which the charge and lattice dynamics are coupled. When applied to hole-doped cuprate superconductors, EXAFS has revealed the presence of internal quantum tunneling polarons (IQTPs). An IQTP arises in EXAFS as a two-site distribution for certain Cu–O pairs, which is also duplicated in inelastic scattering but not observed in standard diffraction measurements. The Cu–Sr pair distribution has been found to be highly anharmonic and strongly correlated to both the IQTPs and to superconductivity, as, for example, in YSr2Cu2.75Mo0.25O7.54(Tc=84 K). In order to describe such nontrivial, anharmonic charge-lattice dynamics, we have proposed a model Hamiltonian for a prototype six-atom cluster, in which two Cu-apical-O IQTPs are charge-transfer bridged through Cu atoms by an O atom in the CuO2 plane and are anharmonically coupled via a Sr atom. By applying an exact diagonalization procedure to this cluster, we have verified that our model indeed produces an intricate interplay between charge and lattice dynamics. Then, by using the Kuramoto model for the synchronization of coupled quantum oscillators, we have found a first-order phase transition for the IQTPs into a synchronized, phase-locked phase. Most importantly, we have shown that this transition results specifically from the anharmonicity. Finally, we have provided a phase diagram showing the onset of the phase-locking of IQTPs as a function of the charge-lattice and anharmonic couplings in our model. We have found that the charge, initially confined to the apical oxygens, is partially pumped into the CuO2 plane in the synchronized phase, which suggests a possible connection between the synchronized dynamic structure and high-temperature superconductivity (HTSC) in doped cuprates.