Electric-field-induced transition between the anticlinic and the synclinic smectic-C surfaces in free-standing films

Anticlinic smectic-C surfaces were found experimentally as ground state structures in free-standing films made of smectic liquid crystals with no anticlinic bulk phases. A mean-field interpretation of this observation is given within a discrete phenomenological model of antiferroelectric liquid crystals, which additionally considers the enhanced order present at the surfaces of the free-standing films. The temperature dependence of the critical electric field that drives the transition between the anticlinic and synclinic smectic-C surfaces is evaluated, and fair agreement with the experimental data is found.