Magnetic field behaviour in $s+is$ and $s+id$ superconductors: twisting of applied and spontaneous fields

Abstract

We consider magnetic field screening and spontaneous magnetic fields in $s+is$ and $s+id$ superconductors both analytically and numerically. We show that in general, the linearized model couples the moduli of order parameters to the magnetic modes. This causes magnetic field screening that does not follow the standard exponential law and hence cannot be characterized by a single length scale: the London penetration length. We also demonstrate that the resulting linear mixed modes, correctly predict spontaneous fields and their orientation. We show that these mixed modes cause external fields to decay non-monotonically in the bulk. This is observed as the magnetic field twisting direction, up to an angle of $\pi /2$, as it decays in the nonlinear model. Finally, we demonstrate that there are two non-degenerate domain wall solutions for any given parameter set. These are distinguished by either clockwise or anti-clockwise interpolation of the inter-component phase difference, each producing a different solution for the other fields. However, only domain wall solutions in $s+id$ systems exhibit magnetic field twisting.

21 pages, 11 figures

References in corpus (9)

• Pairing State with a time-reversal symmetry breaking in FeAs based superconductors
• On the Remarkable Superconductivity of FeSe and its Close Cousins
• Inter-pocket pairing and gap symmetry in Fe-based superconductors with only electron pockets
• Chiral CP^2 skyrmions in three-band superconductors
• Current inversion at the edges of a chiral $\mathbf{p}$-wave superconductor
• Spontaneous currents in a superconductor with s+is symmetry
• Distinguishing between $s+id$ and $s+is$ pairing symmetries in multiband superconductors through spontaneous magnetization pattern induced by a defect
• Microscopic derivation of superconductor-insulator boundary conditions for Ginzburg-Landau theory revisited. Enhanced superconductivity at boundaries with and without magnetic field
• Superconducting junction with tri-component pairing gap functions

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