Structures and velocities of noisy ferroelectric domain walls

Abstract

Ferroelectric domain wall motion is fundamental to the switching properties of ferroelectric devices and is influenced by a wide range of factors including spatial disorder within the material and thermal noise. We build a Landau-Ginzburg-Devonshire (LGD) model of 180${}^{\circ}$ ferroelectric domain wall motion that explicitly takes into account the presence of both spatial and temporal disorder. We demonstrate both creep flow and linear flow regimes of the domain wall dynamics by solving the LGD equations in a Galilean frame moving with the wall velocity $v$. Thermal noise plays a key role in the wall depinning process at small fields $E$. We study the scaling of the velocity $v$ with the applied DC electric field $E$ and show that noise strongly affects domain wall velocities. We also show that the domain wall widens significantly in the presence of thermal noise, especially as the material temperature $T$ approaches the critical temperature $T_c$. These calculations therefore point to the potential of noise and disorder to become control factors for the switching properties of ferroelectric materials, for example for advancement of microelectronic applications.