Abstract

The crucial importance of topological excitations in the physics of superconductivity made Ginzburg—Landau vortices one of the most studied example of topological defects. Multi-band/multi-component superconductors extends usual Ginzburg—Landau theory by considering more than one scalar field (several superconducting order parameters).

Family materials, where superconductivity is multi-band/multi-component, has recently been growing. Because of additional fields and new broken symmetries, the zoo of topological defects is much richer in multi-component systems (e.g. Line-like vortices, fractional vortices, baby skyrmions…). For entropic reasons, thermal fluctuations will induce much more complicated three dimensional solitons, in particular vortex loops.

I will discuss various aspects of topological excitations in multi-component/multi-band superconductors.