The symmetry of the pairing state in iron pnictide superconductor Ba1-xKxFe2As2 is still controversial. At optimal doping (x≈0.4), it is very likely s wave, but for x=1 there are experimental and theoretical arguments for both s wave and d wave. Depending on the choice for x=1, intermediate s+is and s+id states have been proposed for intermediate doping 0.4<x<1. In both states, the time-reversal symmetry is broken and a spontaneous magnetization is allowed. In this work we study a spontaneous magnetization induced by a nonmagnetic defect in the s+is and s+id states by using a perturbation theory and numerical calculations for the Ginzburg-Landau free energy functional. We show that the angular dependence of the magnetization is distinct in these two states due to the difference in symmetry properties of the order parameters. Our results indicate a possible way to distinguish between the s+is and s+id pairing symmetries in multiband superconductors.
|Original language||English (US)|
|Journal||Physical Review B|
|State||Published - Aug 29 2016|
Bibliographical noteFunding Information:
The authors are indebted to James Sauls and Filip Ronning for helpful discussions. The work by S.Z.L. was carried out under the auspices of the U.S. DOE Contract No. DE-AC52-06NA25396 through the LDRD program. The work by A.V.C. was supported by the Office of Basic Energy Sciences, U.S. Department of Energy, under award DE-SC0014402. A.V.C. acknowledges with thanks the support of the Center for Nonlinear Studies, LANL as an Ulam Scholar.
© 2016 American Physical Society.