title: Multistability in planar liquid crystal wells.
abstract: A planar bistable liquid crystal device, reported in Tsakonas et al. [Appl. Phys. Lett. 90, 111913 (2007)], is modeled within the Landau-de Gennes theory for nematic liquid crystals. This planar device consists of an array of square micrometer-sized wells. We obtain six different classes of equilibrium profiles and these profiles are classified as diagonal or rotated solutions. In the strong anchoring case, we propose a Dirichlet boundary condition that mimics the experimentally imposed tangent boundary conditions. In the weak anchoring case, we present a suitable surface energy and study the multiplicity of solutions as a function of the anchoring strength. We find that diagonal solutions exist for all values of the anchoring strength W ≥ 0, while rotated solutions only exist for W ≥ W_{c}>0, where W_{c} is a critical anchoring strength that has been computed numerically. We propose a dynamic model for the switching mechanisms based on only dielectric effects. For sufficiently strong external electric fields, we numerically demonstrate diagonal-to-rotated and rotated-to-diagonal switching by allowing for variable anchoring strength across the domain boundary.
authors.affiliation: Mathematical Institute, University of Oxford, 24-29 St. Giles', Oxford OX1 3LB, United Kingdom. luo@maths.ox.ac.uk
authors.forename: Chong
authors.initials: C
authors.lastname: Luo
authors.forename: Apala
authors.initials: A
authors.lastname: Majumdar
authors.forename: Radek
authors.initials: R
authors.lastname: Erban
mesh_terms: D003198:Computer Simulation; D003460:Crystallization / Q000379:methods*; D050866:Liquid Crystals / Q000737:chemistry*; D008567:Membranes, Artificial; D008956:Models, Chemical; D008958:Models, Molecular; D044367:Phase Transition
chemical_list: D008567:Membranes, Artificial