Order parameter configurations in the Lifshitz-type incommensurate   ferroelectric thin films
  The Dzialoshinskii model of periodic and helicoidal structures has been analyzed without neglecting of the amplitude function oscillations. The amplitude function oscillations are shown to be important for understanding of the nature of the phase function. Analytic consideration is carried out in the limit of small anisotropy (neglecting the cosine term in the Hamiltonian). Surprisingly, the phase jumps survive even in the limit of the vanishing anisotropy. 
Sergey A. Ktitorov, Philip A. Pogorelov