Related papers: Microscopic Hamiltonian for Zn or Ni substituted h…
To describe the scattering of superconducting quasiparticles from non-magnetic (Zn) or magnetic (Ni) impurities in optimally doped high T$_c$ cuprates, we propose an effective Anderson model Hamiltonian of a localized electron hybridizing…
We present a theory of combined nonmagnetic and magnetic impurity scattering in anisotropic superconductors accounting for the momentum-dependent impurity potential. Applying the model to the d-wave superconducting state, we obtain a…
Substitution of isovalent non-magnetic defects, such as Zn, in CuO2 plane strongly modifies the magnetic properties of strongly electron correlated hole doped cuprate superconductors. The reason for enhanced uniform magnetic susceptibility,…
We propose a new model for impurity center formed by a cathion substitute for Cu, like Zn, in CuO_{2} planes. Its main effect on superconducting electrons is due to the non-zero exchange field on O sites, neighbors to the (non-magnetic)…
Ni-substitution effects on the superconductivity and Cu-spin correlation have been investigated in La2-xSrxCu1-yNiyO4 from the electrical resistivity and muon spin relaxation measurements, taking into account the hole trapping by Ni…
We consider the effect of non-magnetic impurities in a $d_{x^2 - y^2}$ superconductor with $\ef$ close to a van Hove singularity. It is shown that the non-trivial density of states (DOS) allows for resonant scattering already at…
The effects of non-magnetic iso-valent defects inside the CuO2 plane(s) on superconducting transition temperature, Tc, dc charge transport, and the bulk magnetic susceptibility, \c{hi}(T), were investigated for the YBa2(Cu1-yZny)3O7-d…
Infinite-layer nickelate superconductors have recently been discovered to share both similarities and differences with cuprate superconductors. Notably, the incorporation of hydrogen (H) through topotactic reduction has been found to play a…
We consider the influence of planar ``magnetic" imperfections which destroy the local magnetic order, such as Zn impurities or $Cu^{2+}$ vacancies, on the low temperature properties of the cuprate superconductors. In the unitary limit, at…
In conventional superconductors, magnetic interactions and magnetic impurity atoms are destructive to superconductivity. By contrast, in some unconventional systems, e.g. superfluid 3He and superconducting UGe2, superconductivity or…
We report muon-spin rotation and neutron-scattering experiments on non-magnetic Zn impurity effects on the static spin-stripe order and superconductivity of the La214 cuprates. Remarkably, it was found that, for samples with hole doping x =…
A theory for the high temperature superconductors is proposed. Holes are spin-1/2, charge e, quasiparticles strongly dressed by spin fluctuations. Based on their dispersion, it is claimed that the experimentally observed van Hove…
The effect of Zn substitution in the CuO2 plane on the superconducting transition temperature, Tc, was studied for the La2-xSrxCu1-yZnyO4 and YBa2(Cu1-yZny)3O7-d compounds over a wide range of hole concentration, p, and Zn content (y). Zn…
High-Tc superconductivity with possible $T_{c}\approx 80K$ has been reported in the single crystal of $\text{La}_{3}\text{Ni}_{2}\text{O}_{7}$ under high pressure. Based on the electronic structure given from the density functional theory…
We examine the influence of Ni impurity in cuprates on the distribution of hole carriers by performing numerically exact diagonalization calculations for a model consisting of Cu3d, Ni3d, and O2p orbitals. Using realistic parameters for the…
Very recently impurity scattering effects on quasiparticles in d-wave superconductors have attracted much attention. Especially, the thermodynamic properties in magnetic fields H are of interest. We have measured the low-temperature…
We propose that the superconductivity recently observed in Nd$_{0.8}$Sr$_{0.2}$NiO$_2$ with critical temperature in the range $9$ K to $15$ K results from the same charge carriers and the same mechanism that we have proposed give rise to…
We propose a microscopic model Hamiltonian to account for impurity doping induced insulator-superconductor transition and the coexistence of antiferromagnetism and superconductivity in the high-Tc cuprates. The crossover from non Fermi…
The families of high-temperature superconductors recently welcomed a new member: hole doped nickelate Nd$_{0.8}$Sr$_{0.2}$NiO$_2$ with a $\sim$15K transition temperature. To understand its emergent low-energy behaviors and experimental…
We describe a method for calculating, within density functional theory, the electronic structure associated with typical defects which substitute for Cu in the CuO2 planes of high-Tc superconducting materials. The focus is primarily on…