Free energy pathways of a multistable liquid crystal device
Abstract
The planar bistable device [Tsakonas \textit{et al., Appl. Phys. Lett.}, 2007, {\textbf{90}}, 111913] is known to have two distinct classes of stable equilibria: the diagonal and rotated solutions. We model this device within the twodimensional Landaude Gennes theory, with a surface potential and without any external fields. We systematically compute a special class of transition pathways, referred to as minimum energy pathways, between the stable equilibria that provide new information about how the equilibria are connected in the Landaude Gennes free energy landscape. These transition pathways exhibit an intermediate transition state, which is a saddle point of the Landaude Gennes free energy. We numerically compute the structural details of the transition states, the optimal transition pathways and the free energy barriers between the equilibria, as a function of the surface anchoring strength. For strong anchoring, the transition pathways are mediated by defects whereas we get defectfree transition pathways for moderate and weak anchoring. In the weak anchoring limit, we recover a cusp catastrophe situation for which the rotated state acts as a transition state connecting two different diagonal states.
 Publication:

Soft Matter
 Pub Date:
 2015
 DOI:
 10.1039/C5SM00578G
 arXiv:
 arXiv:1503.05514
 Bibcode:
 2015SMat...11.4809K
 Keywords:

 Condensed Matter  Soft Condensed Matter;
 Condensed Matter  Materials Science;
 Physics  Computational Physics
 EPrint:
 Soft Matter 11, 4809  4817 (2015)