Smectic-C*alpha phase with two coexistent helical pitch values and a first-order smectic-C*alpha to smectic-C* transition.
Previous results from Kundu using dielectric relaxation have suggested a reentrant antiferroelectric-ferroelectric-antiferroelectric transition in the compound LN36. Our comprehensive studies of this compound using differential optical reflectivity, nonadiabatic scanning calorimetry, null transmission ellipsometry, and resonant x-ray diffraction show that in fact LN36 exhibits the usual phase sequence for chiral smectic liquid crystals: SmA*-SmC*alpha-SmC*-SmC*FI1-SmC*A . Moreover, the SmC*alpha-SmC* transition is a first-order transition, characterized by a discontinuous change in the helical pitch. At temperatures just above the SmC*alpha-SmC* transition, two different values for the helical pitch are simultaneously observed for the first time.
School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455, USA.
B K
BK
McCoy
Z Q
ZQ
Liu
S T
ST
Wang
R
R
Pindak
K
K
Takekoshi
K
K
Ema
A
A
Seed
C C
CC
Huang