Two-dimensional ferroelectrics and homogeneous switching. On the 75th anniversary of the Landau-Ginzburg theory of ferroelectricity

Within the framework of the Landau-Ginzburg (LG) theory, the kinetics of polarization switching in ferroelectric crystals and the transition from domain switching to homogeneous switching in nanosized single-crystal films are considered. It is shown that homogeneous (nondomain) switching can be described in LG theory terms only for two-dimensional ferroelectrics. A review of the experimental results for two-dimensional films of a ferroelectric polymer and barium titanate is given. For ultrathin polymer films, these results are also confirmed by first principles calculations.