Barišić N, Sunko D K
Department of Physics, Faculty of Science, University of Zagreb, Zagreb, 10000 Croatia.
Institute of Solid State Physics, TU Wien, Vienna, 1040 Austria.
J Supercond Nov Magn. 2022;35(7):1781-1799. doi: 10.1007/s10948-022-06183-y. Epub 2022 Mar 18.
A review of the phenomenology and microscopy of cuprate superconductors is presented, with particular attention to universal conductance features, which reveal the existence of two electronic subsystems. The overall electronic system consists of charges, where is the doping. At low dopings, exactly one hole is localized per planar copper-oxygen unit, while upon increasing doping and temperature, the hole is gradually delocalized and becomes itinerant. Remarkably, the itinerant holes exhibit identical Fermi liquid character across the cuprate phase diagram. This universality enables a simple count of carrier density and yields comprehensive understanding of the key features in the normal and superconducting state. A possible superconducting mechanism is presented, compatible with the key experimental facts. The base of this mechanism is the interaction of fast Fermi liquid carriers with localized holes. A change in the microscopic nature of chemical bonding in the copper oxide planes, from ionic to covalent, is invoked to explain the phase diagram of these fascinating compounds.
本文对铜酸盐超导体的现象学和显微镜学进行了综述，特别关注了揭示两个电子子系统存在的普遍电导特征。整个电子系统由电荷组成，其中是掺杂量。在低掺杂时，每个平面铜氧单元恰好有一个空穴被局域化，而随着掺杂量和温度的增加，空穴逐渐离域并成为巡游的。值得注意的是，巡游空穴在整个铜酸盐相图中表现出相同的费米液体特性。这种普遍性使得能够简单地计算载流子密度，并对正常态和超导态的关键特征有全面的理解。本文提出了一种与关键实验事实相符的可能超导机制。该机制的基础是快速费米液体载流子与局域空穴的相互作用。为了解释这些迷人化合物的相图，人们提出了氧化铜平面中化学键微观性质从离子键到共价键的变化。
