Spontaneous polarization and phase transition temperature of dobambc mixed with D(+)- and L(-)-carvone

Abstract

Spontaneous polarization (P _s ) of D(+)-DOBAMBC mixed with D(+)- and L(-)-carvone were studied using Pepinsky bridge. The P _s oscillates with carvone concentration at its low concentration regime and monotonically decreases at high concentration one. At low temperature, the P _s in the mixture with D(+)-carvone shows opposite dependence to that with L(-)-carvone. While, these tendency is somewhat blurred at high temperature, which is quite different from the mixture of achiral smectic C with chiral nonmesogenic impurity. Maximum value of P _s in L(-)-carvone 4.15 mol% mixture is about 1.12 times as large as that of pure one. No dependence of the critical index of P _s was found on carvone concentration. Phase transition temperature T _c between S_A and S*_C also oscillates as the carvone concentration is increased. Generally, the influence of the chiral impurity with opposite rotatory sign is stronger than that with the same one.