Alladi Ramakrishnan Hall

Skyrmion-like textures in superconductors with competing orders

V Saran

IIT Madras

Superconductivity is locally suppressed within vortex cores. Taking advantage of this, competing ordering tendencies can manifest themselves within the core region. In strong magnetic fields, vortices appear in close proximity leading to overlap of ordering textures. We study this physics using the SO(3) theory of competing orders, wherein superconductivity and a scalar order form a three-component vector field. We consider a spherical surface with a radial magnetic flux that creates two vortices. To set up the problem, we construct a vector potential where the Dirac string has been flattened into a sheet at the equator. We find stationary solutions where both vortex cores develop competing order in (a) the same sense, and (b) opposite senses. The latter represents a topologically stable vector configuration analogous to a single skyrmion. We add a spin-orbit coupling term that does not change the nature of the solutions. However, it lowers the energy of the skyrmionic solution, making it the ground state beyond a threshold value.