Degeneracy lifting due to thermal fluctuations around the frustration point between anticlinic antiferroelectric SmC*(A) and synclinic ferroelectric SmC*

作者：Sandhya K L^*; Chandani A D L; Fukuda Atsuo; Vij Jagdish K; Emelyanenko A V; Ishikawa Ken

来源：Physical Review E, 2013, 87(1): 012502.

DOI：10.1103/PhysRevE.87.012502

In the binary mixture phase diagram of MC881 and MC452, the borderline between anticlinic antiferroelectric SmC*(A) and synclinic ferroelectric SmC* becomes apparently parallel to the temperature ordinate axis at the critical concentration r(c). The free energy difference between SmC*(A) and SmC* is extremely small in a wide temperature range near r(c). In such circumstances, by observing Bragg reflection spectra due to the director helical structure and electric-field-induced birefringence, we have observed the continuous change from SmC*(A) to SmC* for r less than or similar to r(c) and the gradual growth of the full-pitch band over 5 degrees C or more in the apparent SmC* temperature region for r greater than or similar to r(c). These intriguing phenomena have been explained, successfully at least in the high-temperature region, by a thermal equilibrium between the synclinic and anticlinic orderings and the resulting Boltzmann distribution for the ratio between them; the thermal equilibrium is considered to be attained in a nonuniform defect-assisted way through solitary waves moving around dynamically. We have also discussed qualitatively an important role played by the effective long-range interlayer interactions in the low-temperature region. DOI: 10.1103/PhysRevE.87.012502

• 出版日期2013-1-14