Role of anisotropic impurity scattering in anisotropic superconductors

Abstract

A theory of nonmagnetic impurities in an anisotropic superconductor including the effect of anisotropic (momentum-dependent) impurity scattering is given. It is shown that for a strongly anisotropic scattering the reduction of the pair-breaking effect of the impurities is large. For a significant overlap between the anisotropy functions of the scattering potential and that of the pair potential and for a large amount of anisotropic scattering rate in impurity potential the superconductivity becomes robust vis a vis impurity concentration. The implications of our result for YBCO high-temperature superconductor are discussed. The experimental data of electron irradiationinduced T c suppression (Phys. Rev. B50, 15967 (1994)) is understood quantitatively and a good qualitative agreement with the ion (N e + ) damage and P r substitution-induced T c decrease data (Phys. Rev. B50, 3266 (1994)) is obtained. 74.62.Dh Typeset using REVT E X 1

Microwave conductivity ofd-wave superconductors with extended impurities

“…12, which is close to the highest values of T c measured for the BSCCOcompounds. Extended impurities, on the other hand, act mainly as small angle scatterers and affect T c much less than isotopic scatterers 34,35 . This allows us to assess model (i), which consists only of weak pointlike scatterers, as very unlikely and to conclude that at least a large fraction of the disorder in the BSCCO compounds should be attributed to extended scatterers.…”

Substitution for Cu in the electron-doped infinite-layer superconductorSr0.9La0.1CuOJung1, Kim2, Park3 et al. 2002Phys. Rev. B33140View full textAdd to dashboardCite

“…This behavior of T c is strongly contrasted with that of conventional superconductors, where the reduction of T c is stronger for magnetic ion impurities, but nearly absent for nonmagnetic ion impurities. This difference led to the theoretical formulation of an unconventional pairing mechanism and a symmetry of the order parameter for high-temperature superconductor [16][17][18][19][20][21][22][23][24][25][26][27].…”

Superconductivity in the pseudogap state in the hot spot model: The influence of impurities and the phase diagram

“…Another interesting possibility to explain the "slowing down" of T c suppression is connected with an account of anisotropy of impurity scattering, analyzed in detail in Refs. [10,22]. This effect can be rather easily included in our calculational scheme.…”