Ye Fangfu, Mukhopadhyay Ranjan, Stenull Olaf, Lubensky T C
Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
Phys Rev Lett. 2007 Apr 6;98(14):147801. doi: 10.1103/PhysRevLett.98.147801. Epub 2007 Apr 5.
Nematic elastomers with a locked-in anisotropy direction exhibit semisoft elastic response characterized by a plateau in the stress-strain curve in which stress does not change with strain. We calculate the global phase diagram for a minimal model, which is equivalent to one describing a nematic in crossed electric and magnetic fields, and show that semisoft behavior is associated with a broken symmetry biaxial phase and that it persists well into the supercritical regime. We also consider generalizations beyond the minimal model and find similar results.
