Entropy-Stabilized Smectic CPhase in a System of Zigzag-Shaped Molecules

We report Monte Carlo simulations of a system of rigid zigzag-shaped molecules that demonstrate that simple excluded-volume interactions are sufficient to produce a fluid tilted lamellar [smectic C (SmC)] liquid crystal phase. The molecules are composed of three rigidly linked hard spherocylinders arranged in a zigzag fashion. By varying the zigzag angle we have mapped out the whole phase diagram as a function of pressure and zigzag angle Ψ. For Ψ between 35^∘ and 80^∘ our model simulation exhibits the SmC phase. This is the first conclusive evidence where steric interactions arising out of molecular shape alone induce the occurrence of the SmC phase for a wide range of zigzag angles. For smaller Ψ, a transition from tilted crystal to crystal is observed.