By using band structure calculations of quantum mechanical theory, some important peaks of DoS (Density of States) were obtained and classified based on crystal structure laws of cuprate superconductivity. In particular, the orbital interactions of the in-plane and out-of-plane ions of the copper-oxygen plane were investigated. The position, half-width, and height of DOS peak features were collected for all 35 typical curate systems which have critical temperature maximum data from the works of literature. By training test of 7 common machine learning algorithms, the relationship between the Tc maximum values and these orbital interaction parameters were mined. It was found that the key features of the orbital interaction affecting the Tc maximum were not only the flat band but also a new interaction between core orbitals in a deeper energy band position.
Within the spin-fermion model for cuprate superconductors, the influence of the intersite Coulomb interactions $V_2$ and $V_2'$ between holes located at the next-nearest-neighbor oxygen ions of CuO$_2$ plane on the implementation of the d_{x^2-y^2}-wave pairing is studied. It is shown that d-wave pairing can be suppressed only for unphysically large values of $V_2$ and $V_2'$.
Both the pairing and the pair-breaking modes lead to similar kinks of the electron dispersion curves in superconductors, and therefore the photoemission spectroscopy can not be straightforwardly applied in search for their pairing glue. If the momentum-dependence of the normal and anomalous self-energy can be neglected, manipulation with the data does allow us to extract the gap function $Δ(ω)$ and therefore also the pairing glue. However, in the superconducting cuprates such procedure may not be justified. In this paper we point out that the pairing glue is more directly visible in the spectr…
Cooper's one pair problem is investigated for a 2D lattice in the background of both passive and active Fermi sea in a weakly correlated environment. Boson exchange mechanisms involving excitons as well as phonons are invoked for pairing in the s- wave channel. The important quantities calculated are pairing energy and coherence length as functions of bosonic energy, attracted coupling constant and band filling factor. Comparison of our theoretical results with those from experiments on overdoped cuprate superconductors and other type of theoretical calculations show electronic mechanism to be…
We perform a numerical simulation of a three-band Hubbard model with two CuO$_2$ planes and a single CuO chain layer for YBCO cuprates. The spin-fluctuation mediated pairing interaction is computed within the multiband random-phase approximation, and its pairing eigenvalues and eigenfunctions are solved as a function of chain state filling factor $n_c$. We find that for the intrinsic value of $n_c$ in YBCO samples, one obtains the usual $d$-wave pairing symmetry. However, if we dope the chain layers with holes, while keeping the plane states doping fixed, the leading pairing symmetry solution …
Cooper's formalism for fermionic pairing has been revisited considering upto 3rd neighbour hopping terms, firstly with a Fermi liquid like background on a square lattice keeping in mind the overdopped cuprates. Then the whole scheme is repeated with a Marginal Fermi liquid- like background, taking into account the self energy correction of the mobile electrons to include a more realitic density of states in the calculation. Detailed comparison of our theoretical results with those from experiments strongly supports the Marginal Fermi liquid- like character of the normal phase with exciton medi…
The vortex transport entropy in the mixed state of the cuprate superconductors YBa$_2$Cu$_3$O$_{7-δ}$ and Bi$_2$Sr$_2$CaCu$_2$O$_{8+x}$ at the maximum Nernst or Ettingshausen signal below $T_c$ is discussed. The vortex transport entropy per CuO$_2$ double layer in the cuprate epitaxial films is found to be close to the Boltzmann constant.
Two-Orbital Model Explains the Higher Transition Temperature of the Single-Layer Hg-Cuprate Superconductor Compared to That of the La-Cuprate Superconductor
Short review of the topical comprehension of Cuprate High-Temperature Superconductors, featuring structural and metallurgical aspects that optimize their superconducting properties with respect to technical applications.
Nature of the quantum insulator to superconductor and superconductor to normal state transitions in cuprate superconductors
本文用量子临界现象的标度理论详细分析了La $_{2-x}$ Sr $_{x}$ CuO $_{4}$，Y $_{0.8}$ Ca $_{0.2}$-123，Tl-1212和Tl-2201的各种超导性质。我们的结果包括：实验数据是完全符合的2D绝缘体到超导体（ISQ）的过渡在欠掺杂的限制。量子临界性质似乎是相当于那些肮脏的2D玻色子系统与长程库仑相互作用。与以前的证据一起，这种转变似乎是铜酸盐超导体的一般特征。3D超导体到正常态的量子跃迁（SNQ）被证明不那么独特。需要更多的实验数据来明确地解决这种转变的性质。
Novel Isotope Effects on the Pairing Pseudogap in High-$T_{c}$ Cuprates: Evidences for Polaronic Metal and Precursor BCS-Like Pairing of Large Polarons
Since their experimental discovery in 1989, the electron-doped cuprate superconductors have presented both a major challenge and a major opportunity. The major challenge has been to determine whether these materials are fundamentally different from or essentially similar to their hole-doped counterparts; a major opportunity because answering this question would strongly constrain the possible explanations for what is the essential physics that leads to high temperature superconductivity in the cuprates, which is still not agreed upon. Here we argue that experimental results over the past 30 ye…
