title: Phase behavior of bent-core molecules.
abstract: Recently, a new class of smectic liquid crystal phases characterized by the spontaneous formation of macroscopic chiral domains from achiral bent-core molecules has been discovered. We have carried out Monte Carlo simulations of a minimal hard spherocylinder dimer model to investigate the role of excluded volume interactions in determining the phase behavior of bent-core materials and to probe the molecular origins of polar and chiral symmetry breaking. We present the phase diagram of hard spherocylinder dimers of length-diameter ratio of 5 as a function of pressure or density and dimer opening angle psi. With decreasing psi, a transition from a nonpolar to a polar smectic A phase is observed near psi=167 degrees, and the nematic phase becomes thermodynamically unstable for psi<135 degrees. Free energy calculations indicate that the antipolar smectic A (SmAP(A)) phase is more stable than the polar smectic A phase (SmAP(F)). No chiral smectic or biaxial nematic phases were found.
authors.affiliation: Condensed Matter Laboratory, Department of Physics, and Ferroelectric Liquid Crystal Materials Research Center, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: Yves
authors.initials: Y
authors.lastname: Lansac
authors.forename: Prabal K
authors.initials: PK
authors.lastname: Maiti
authors.forename: Noel A
authors.initials: NA
authors.lastname: Clark
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Glaser