Cross-coupling of Tetrahedratic Order

We discuss how tetrahedratic order couples to external fields, forces and other variables [1-3]. In particular, we show that the application of an external electric field to a tetrahedratic phase induces quadrupolar orientational order, thus inducing a nematic phase in a field. We discuss a linear gradient term coupling tetrahedratic and quadrupolar order and show that this term could explain the ambidextrous chiral domains observed in nematic phases formed by achiral banana-shaped molecules. [1] H.R. Brand, H. Pleiner and P.E. Cladis, Eur. Phys. J. E7, 163 (2002). [2] P.E. Cladis, H. Pleiner and H.R. Brand, Eur.Phys. J E11, 283 (2003). [3] H.R. Brand, H. Pleiner and P.E. Cladis, Physica A, in print.