Theoretical Model of Vertically Stacked Domains in Nematic Liquid Crystals

In the typical nematic liquid crystal (LC) geometry, the director profile under the effect of an applied field has a quasi-parabolic configuration. Previously, other possible profiles of the LC director were explored under the effects of mutually perpendicular electric and magnetic fields. We discovered the metastable states with an oscillatory director profile in the vertical direction are possible under the effect of an applied electric field only. We explore these states theoretically both through energy minimization and a differential equation approach. Under weak applied electric fields, we find small oscillations, which evolve into standard soliton-like domain walls as the applied field is increased. We develop a simple analytic model to predict the thickness of the domain wall that compares well with our numerical calculations. Furthermore, we investigate effects of domain walls on the optical characteristics of LC-based devices. For instance, we find the shift in the transmittance through the LC cell, from low to high voltages as domain walls are introduced, which can be used to create an optical shutter.