A Landau Primer for Ferroelectrics
  In this review, we hope to give the reader a self-contained contemporary presentation of the application of Landau theory to ferroelectrics. We begin by developing Landau theory for homogenous bulk ferroelectrics and then consider the finite-size (thin film) case within the related Landau-Ginzburg approach. Next we discuss the treatment of inhomogeneity within this framework. We end with a number of open questions for future pursuits. 
P. Chandra and P.B. Littlewood