Effects of impurities on superconductivity in noncentrosymmetric compounds

Abstract

We microscopically derive the Ginzburg-Landau free energy functional for a noncentrosymmetric superconductor with a large spin-orbit splitting of the electron bands, in the presence of nonmagnetic impurities. The critical temperature is found to be suppressed by disorder, both for conventional and unconventional pairing, in the latter case according to the universal Abrikosov-Gor'kov function. The impurity effect on the upper critical field turns out to be non-universal, determined by the pairing symmetry and the band structure. In a BCS-like model, Tc is not affected, while Hc2 increases with disorder. For unconventional pairing, both Tc and Hc2 are suppressed by disorder.

Non-centrosymmetric Heavy-Fermion Superconductors

“…Such a strong suppression of T c with increasing impurities/defects is typical of unconventional parity-conserving superconductors [27]. Recent theoretical works [111,112] considered impurity effects on the critical temperature of superconductors without inversion symmetry. It was found that impurity scattering leads to a functional form of T c that, up to a prefactor, is the same as the one for unconventional superconductor with inversion symmetry: ln(T c /T c0 ) = α Ψ ( .…”

Possible triplet superconductivity in the quasi-one-dimensional conductor Li0.9Mo6O17

“…[27]). To derive the gap equation for superconducting order parameter ∆(y), we use Gor'kov's equations for unconventional superconductivity [30][31][32]. As a result of the calculations, we obtain:…”

Characterizingp-wave superconductivity using the spin structure of Shiba states

“…Ever since the discovery of strontium ruthenate as one the first unconventional superconductors (SCs) more than thirty years ago, 1 the search for the symmetry of Cooper pairs 2,3 has been among the most important tasks to be addressed in order to characterize new superconducting materials. In the past decade, many new SCs with broken inversion symmetry have been discovered.…”