Nonlinear magneto-optical response ofs- andd-wave superconductors

Abstract

The nonlinear magneto-optical response of s-and d-wave superconductors is discussed. We carry out the symmetry analysis of the nonlinear magneto-optical susceptibility in the superconducting state. Due to the surface sensitivity of the nonlinear optical response for systems with bulk inversion symmetry, we perform a group-theoretical classification of the superconducting order parameter close to a surface. The mixing of singlet and triplet pairing states induced by spin-orbit coupling is systematically taken into account. We show that the interference of singlet and triplet pairing states leads to an observable contribution of the nonlinear magnetooptical Kerr effect. This effect is not only sensitive to the anisotropy of the gap function but also to the symmetry itself. In view of the current discussion of the order-parameter symmetry of high-T c superconductors, results for a tetragonal system with bulk singlet pairing for various pairing symmetries are discussed.

Selection rules for Cooper pairing in two-dimensional interfaces and sheets

“…It follows that, if the thin film still displays superconductivity, TRS must be restored in the condensate and the triplet component of the order parameter must be aligned parallel to the plane of the system. More specifically, from a pure symmetry point of view, the most natural 33 candidate pairing state is e (1,i) transforming under the IR E subduced from E g of D 4h , which is the IR of the bulk pairing state Δ k = iσ y (k x + ik y )k z . 30,34 Since this state is suppressed if assumption (i) holds, superconductivity is likely to disappear in the thin-layer system, which, in addition, implies that inversionsymmetry breaking impurities are expected to be strongly pair breaking.…”

Symmetry analysis of second-harmonic generation at surfaces of antiferromagnets

“…[15]. Nonlinear optical effects were invoked to explain the behavior of lasers in magnetic fields [16], to investigate high temperature superconductors [17,18], and to study structures composed from alternately ferro-and antiferromagnetically ordered thin films [19]. One of the first theoretical investigations of the possibility to apply nonlinear optics to antiferromagnetism was performed by Kielich and Zawodny [20].…”