  In the micro- and nanoscale ferroelectric samples, the formation and the
growth of domains are the usual stages of the polarization switching mechanism.
By assuming the weak polarization anisotropy and by solving the
Ginzburg-Landau-Khalatnikov equation we have explored an alternative mechanism
which consists in ferroelectric switching induced by vortex formation. We have
studied the polarization dynamics inside a ferroelectric circular capacitor
where switching leads to formation of a metastable vortex state with a
rotational motion of polarization. Our results are consistent with recent
first-principa simulations [I. I. Naumov and H. X. Fu, Phys. Rev. Lett. 98,
077603 (2007)] and with experiments in PbZr0.2Ti0.8O3 [A.Gruverman et al, J.
Phys. Condens. Matter 20 342201(2008)] and demonstrate that vortex induced
polarization switching can be the effective mechanism for circular
nano-capacitors.
