Properties of skyrmions and multi-quanta vortices in chiral p-wave superconductors

Abstract

Chiral p-wave superconducting state supports a rich spectrum of topological excitations different from those in conventional superconducting states. Besides domain walls separating different chiral states, chiral p-wave state supports both singular and coreless vortices also interpreted as skyrmions. Here, we present a numerical study of the energetic properties of isolated singular and coreless vortex states as functions of anisotropy and magnetic field penetration length. In a given chiral state, single quantum vortices with opposite winding have different energies and thus only one kind is energetically favoured. We find that with the appropriate sign of the phase winding, two-quanta (coreless) vortices are always energetically preferred over two isolated single quanta (singular) vortices. We also report solutions carrying more flux quanta. However those are typically more energetically expensive/metastable as compared to those carrying two flux quanta.

Vortex liquid phase in the p -wave ferromagnetic superconductor UCoGe

“…This recovered spin degeneracy [16] is also favorable to the appearance of non-singular vortices, i.e., vortices where the order parameter does not vanish completely in the core. Such vortices have been predicted to occur for superconductors with multicomponent order parameters (see review [39]), either from the orbital degrees of freedom [40] or from the spin degrees of freedom in a triplet state [41,42], and this field of research on exotic vortices notably in p-wave superconductors [43] or in Bose-Einstein condensate is still very active [44]. For multicomponent order parameters, it is possible that zeros of the two components of the superconducting order parameter are located at different points in space, leading to "non-singular" vortex cores (non-zero order parameter in the core).…”

Nematic Skyrmions in Odd-Parity Superconductors

“…The north (respectively, south) pole signals zero of ∆+ (respectively ∆−), and thus the position of respective HQVs. From this one, can see structural difference of nematic Skyrmions, compared to Skyrmions in chiral superconductors [28]. Here the solution has clearly the form of weakly interacting well-separated Skyrmions with unit topological charge each.…”

Self-dual solitons in a generalized Chern-Simons baby Skyrme model

“…Skyrmions has been predicted for K 2 Fe 4 Se 5 material where superconductivity emerges at room temperature and stable Skyrmions become Cooper pairs through a quantum anomaly [15]. Further approaches have been made on this field [16][17][18][19][20] and also analogies between vortex in superconductors systems and Skyrmions in magnetic materials. Skyrmion crystal with a triangular array in magnetic systems was shown to have strong similarities with Abrikosov vortex lattice in type-II superconductors [21].…”