Pelc D, Popčević P, Požek M, Greven M, Barišić N
Department of Physics, Faculty of Science, University of Zagreb, Bijenička cesta 32, HR-10000 Zagreb, Croatia.
School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455, USA.
Sci Adv. 2019 Jan 25;5(1):eaau4538. doi: 10.1126/sciadv.aau4538. eCollection 2019 Jan.
The discovery of high-temperature superconductivity in cuprates ranks among the major scientific milestones of the past half century, yet pivotal questions regarding the complex phase diagram of these materials remain unanswered. Generally thought of as doped charge-transfer insulators, these complex oxides exhibit pseudogap, strange-metal, superconducting, and Fermi liquid behavior with increasing hole-dopant concentration. Motivated by recent experimental observations, here we introduce a phenomenological model wherein exactly one hole per planar copper-oxygen unit is delocalized with increasing doping and temperature. The model is percolative in nature, with parameters that are highly consistent with experiments. It comprehensively captures key unconventional experimental results, including the temperature and the doping dependence of the pseudogap phenomenon, the strange-metal linear temperature dependence of the planar resistivity, and the doping dependence of the superfluid density. The success and simplicity of the model greatly demystify the cuprate phase diagram and point to a local superconducting pairing mechanism.
铜酸盐中高温超导性的发现是过去半个世纪的重大科学里程碑之一，但关于这些材料复杂相图的关键问题仍未得到解答。这些复杂氧化物通常被认为是掺杂的电荷转移绝缘体，随着空穴掺杂浓度的增加，它们会呈现出赝能隙、奇异金属、超导和费米液体行为。受近期实验观察结果的启发，我们在此引入一个唯象模型，其中随着掺杂和温度的增加，每个平面铜氧单元恰好有一个空穴离域。该模型本质上是渗流性的，其参数与实验高度一致。它全面捕捉了关键的非常规实验结果，包括赝能隙现象的温度和掺杂依赖性、平面电阻率的奇异金属线性温度依赖性以及超流密度的掺杂依赖性。该模型的成功与简单极大地揭开了铜酸盐相图的神秘面纱，并指向一种局域超导配对机制。
