Related papers: Testing the itinerancy of spin dynamics in superco…
Starting from the generalized t-J-G model Hamiltonian, we analyze the spin response in the superconducting cuprates taking into account both local and itinerant spin components which are coupled to each other self-consistently. Derived…
We describe the relation between spin fluctuations and superconductivity in a highly-ordered sample of YBaCu3O6.5 using both polarized and unpolarized neutron inelastic scattering. The spin susceptibility in the superconducting phase…
We show that recent measurements of the magnetic field dependence of the magnetization, specific heat and resistivity of overdoped $T_c \sim 17K$ $Tl_{2}Ba_{2}CuO_{6+\delta}$ in the vicinity of the superconducting $H_{c2}$ imply that the…
Understanding the overall features of magnetic excitation is essential for clarifying the mechanism of Cooper pair formation in iron-based superconductors. In particular, clarifying the relationship between magnetism and superconductivity…
Local magnetic properties around a nonmagnetic impurity are investigated in high-Tc cuprate superconductors. We consider a model two-dimensional d-wave superconductor with strong antiferromagnetic (AF) spin fluctuations and calculate the…
We comment on a recent paper [Phys. Rev. Lett. 97, 070401 (2006): quant-ph/0603229] concerning rubidium atoms trapped near a superconducting niobium surface at ~4K. This seeks to calculate the rate of atomic spin flips induced by thermal…
The superconducting gap - an energy scale tied to the superconducting phenomena-opens on the Fermi surface at the superconducting transition temperature (TC) in conventional BCS superconductors. Quite differently, in underdoped high-TC…
The electronic structure of the high-Tc cuprates is studied in terms of "large-U" and "small-U" orbitals. A striped structure and three types of quasiparticles are obtained, polaron-like "stripons" carrying charge, "svivons" carrying spin,…
While the pronounced doping dependence of the quasiparticle spectral weight in the antinodal region of the superconducting cuprates, as seen by ARPES, unambiguously points to the magnetic origin of the strong electron-boson coupling there,…
We reviewed our various results on rutheno-cuprate magneto-superconductors RuSr2GdCu2O8(Ru-1212) and RuSr2(Gd0.75Ce0.25)2Cu2O10(Ru-1222). It is observed, that it is difficult to control the oxygen content of Ru-1212, though the same is…
We report a comprehensive polarized and unpolarized neutron scattering study of the evolution of the dynamical spin susceptibility with temperature and doping in three underdoped single crystals of the \YBCO{6+x} high temperature…
High-temperature superconductivity occurs near antiferromagnetic instabilities and nematic state. Debate remains on the origin of nematic order in FeSe and its relation with superconductivity. Here, we use transport, neutron scatter- ing…
Polarized inelastic neutron scattering experiments were performed to study magnetic excitations in the normal and superconducting phases of Co-underdoped BaFe$_2$As$_2$, which exhibits coexistence of antiferromagnetic order and…
The quantum spin fluctuations of the S = 1/2 Cu ions are important in determining the physical properties of the high-transition temperature (high-Tc) copper oxide superconductors, but their possible role in the electron pairing for…
We study the interplay between superconductivity and antiferromagnetic spin fluctuations in electron-doped cobaltate Na$_{x}$CoO$_{2}\cdot y$H$_{2}$O based on the kinetic energy driven superconductivity mechanism. We show that the…
We use inelastic neutron scattering to systematically investigate the Ni-doping evolution of the low-energy spin excitations in BaFe2-xNixAs2 spanning from underdoped antiferromagnet to overdoped superconductor (0.03< x < 0.18). In the…
We summarize the present status of the theories of spin fluctuations in dealing with the anomalous or non-Fermi liquid behavior and unconventional superconductivity in strongly correlated electron systems around their magnetic instabilities…
There is strong evidence that magnetic interactions play a crucial role in the mechanism driving high-temperature superconductivity in cuprate superconductors. To investigate this further we have done neutron scattering experiments on the…
Electron quasiparticles play a crucial role in simplifying the description of many-body physics in solids with surprising success. Conventional Landau's Fermi-liquid and quasiparticle theories for high-temperature superconducting cuprates…
We perform time resolved photoelectron spectroscopy measurements of optimally doped $\tn{Bi}_2\tn{Sr}_2\tn{CaCu}_2\tn{O}_{8+\delta}$ (Bi-2212) and $\tn{Bi}_2\tn{Sr}_{2-x}\tn{La}_{x}\tn{Cu}\tn{O}_{6+\delta}$ (Bi-2201). The electrons dynamics…