相关论文: Impurity-induced smearing of the spin resonance pe…
Mechanism of unconventional superconductivity in FeSe has been intensely scrutinized recently because of a variety of exotic properties unprecedented for other iron-based superconductors. A central unanswered question concerns the origin of…
The impurity effects are studied for the BiS_{2}- layered superconductors based on a two orbital model with the Bogoliubov-de-Gennes technique. The superconducting critical temperature (T_{c}) as a function of the mpurity concentration is…
Nonmagnetic Zn impurities are known to strongly suppress superconductivity. We review their effects on the spin excitation spectrum in $\rm YBa_2Cu_3O_{7}$, as investigated by inelastic neutron scattering measurements.
Effects of disorder on superconducting properties of noncentrosymmetric compounds are discussed. Elastic impurity scattering, even for scalar impurities, leads to a strongly anisotropic mixing of the electron states in the bands split by…
Based on an effective Hamiltonian with the binary alloy disorder model defined in the triangular lattice, the impurity scattering effects on the density of states and especially on the spin-lattice relaxation rate $1/T_1$ of $p_x+ip_y$-wave…
From heavy fermions to cuprates and iron pnictides, a spin resonance is a staple of nearly magnetic superconductors. Possible explanations include a two-particle bound state or loss of magnon damping in the superconductor. While both…
Within the two-orbital model for BiS$_{2}$-based superconductors, the effect from a single nonmagnetic impurity scattering on the superconducting-state is investigated in terms of the T-matrix approach. By considering three kinds of the…
The effects of nonmagnetic impurities on the neutron scattering intensity are studied for a model of the copper oxide layers in the normal state. The contribution to the Q=(pi,pi) neutron scattering intensity from processes involving the…
We present a microscopic study of the nuclear magnetic relaxation rate 1/T1 based on the five-orbital model for iron-based superconductors. We mainly discuss the effect of the "inelastic" quasi-particle damping rate {\gamma} due to…
The influence of La non magnetic impurities on the spin dynamics of CeCoIn$_{5}$ was studied by inelastic neutron scattering. In La-substituted systems, the spin resonance peak (observed at $\Omega_{res}=0.55 meV$ in the pure system) is…
Electronic Raman scattering measures a polarization-dependent scattering intensity which can provide information about the location of nodes in the energy gap of an unconventional superconductor as well as its overall symmetry. In this…
An optimally doped iron-based superconductor LaFeAsO$_{0.92}$F$_{0.08}$ with $T_c = 29$ K has been studied by inelastic powder neutron scattering. The magnetic excitation at $Q=1.15$ \AA$^{-1}$ is enhanced below $T_c$, leading to a peak at…
A single impurity problem is investigated for multiband s-wave superconductors with different sign order parameters (+-s-wave superconductors) suggested in Fe-pnictide superconductors. Not only intraband but also interband scattering is…
Superconductivity appears to compete against the spin-density-wave in Fe pnictides. However, optimally cobalt doped samples show a quasi-two-dimensional spin excitation centered at the (0.5, 0.5, L) wavevector, "the spin resonance peak",…
The magnetic excitation spectrum of a YBa_2 Cu_3 O_7 crystal containing 0.5% of nonmagnetic (Zn) impurities has been determined by inelastic neutron scattering. Whereas in the pure system a sharp resonance peak at E ~ 40 meV is observed…
We consider the spin response within the five-orbital model for iron-based superconductors and study two cases: equal and unequal gaps in different bands. In the first case, the spin resonance peak in the superconducting state appears below…
We report neutron inelastic scattering measurements on the stoichiometric iron-based superconductor LiFeAs. We find evidence for (i) magnetic scattering consistent with strong antiferromagnetic fluctuations, and (ii) an increase in…
The spin resonance observed in the inelastic neutron scattering data on Fe-based superconductors has played a prominent role in the quest for determining the symmetry of the order parameter in these compounds. Most theoretical studies of…
In conventional s-wave superconductors, only magnetic impurities exhibit impurity bound states, whereas for an s+- order parameter they can occur for both magnetic and non-magnetic impurities. Impurity bound states in superconductors can…
Inelastic neutron scattering and susceptibility measurements have been performed on the optimally-doped Fe-based superconductor FeTe(0.5)Se(0.5), which has a critical temperature, Tc of 14 K. The magnetic scattering at the stripe…