Landau Theory of Biaxial and Uniaxial Nematic Liquid Crystals

Abstract
A Landau theory is developed for uniaxial and biaxial nematic phases, based on the order parameter S αβ ij . Four nematic phases, two uniaxial and two biaxial, are predicted and their symmetries are discussed. A typical phase diagram is presented and comparisons are made with earlier mean field theories and Landau theories based on a second rank tensor order parameter.