Biaxial smectic-A⋊ phase and its possible misidentification as a smectic-Cα* phase
نویسنده
چکیده
∗ ∗ ∗ The biaxial smectic-A (Sm-AB ) phase, appearing in the phase sequence Sm-A –Sm-AB–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-AB ∗ –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-Cα ∗ phase. As such, it is possible that the Sm-AB ∗ phase could be misidentified as a Sm-Cα ∗ phase. Ways to distinguish the two phases are discussed.
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