title: Biaxial smectic-A* phase and its possible misidentification as a smectic-Cα* phase.
abstract: The biaxial smectic-A* (Sm-A(B)*) phase, appearing in the phase sequence Sm-A*-Sm-A(B)*-Sm-C*, is analyzed using Landau theory. It is found to possess a helical superstructure with a pitch that is significantly shorter than the pitch of the Sm-C* helical superstructure. The Sm-A(B)*-Sm-C* transition can be either first or second order, and correspondingly there will be either a jump or continuous variation in the pitch. The behaviors of the birefringence and electroclinic effect are analyzed and found to be similar to those of a Sm-C(α)* phase. As such, it is possible that the Sm-A(B)* phase could be misidentified as a Sm-C(α)* phase. Ways to distinguish the two phases are discussed.
authors.affiliation: Department of Physics, California Polytechnic State University, San Luis Obispo, California 93407, USA.
authors.forename: Karl
authors.initials: K
authors.lastname: Saunders