title: Sequence of four orthogonal smectic phases in an achiral bent-core liquid crystal: evidence for the SmAP(α) phase.
abstract: The mesomorphic properties of an achiral bent-core liquid crystal derived from 4-cyanoresorcinol are studied by polarizing optical microscopy, x-ray diffraction, and second harmonic electro-optic response. It shows a novel sequence of four nontilted or orthogonal smectic phases on cooling: SmA-SmAP(R)-SmAP(X)-SmAP(A). Here SmAP(X) is the new orthogonal polar uniaxial smectic phase. The electric-field-induced transformations in the SmAP(X) phase give rise to two biaxial states separated by a uniaxial one. The second harmonic electro-optic response in this phase is interpreted in terms of the polar interaction with the electric field. A comparison of the experimental results with the next-nearest-neighbor model for the structure of the SmAP(X) phase shows it to be an SmAP(α) phase.
authors.affiliation: Department of Electronic and Electrical Engineering, Trinity College, University of Dublin, Dublin 2, Ireland.
authors.forename: Y P
authors.initials: YP
authors.lastname: Panarin
authors.forename: M
authors.initials: M
authors.lastname: Nagaraj
authors.forename: S
authors.initials: S
authors.lastname: Sreenilayam
authors.forename: J K
authors.initials: JK
authors.lastname: Vij
authors.forename: A
authors.initials: A
authors.lastname: Lehmann
authors.forename: C
authors.initials: C
authors.lastname: Tschierske