Dielectric Dynamics and Polar Nanoregions in Ferroelectric Nematic Liquid Crystals of the nJK Series
Year: 2026
Type: preprint
Abstract: This study presents a comprehensive investigation of polarization dynamics and phase transitions in a novel homologous series of polar nematics (nJK, n=1-5) using broadband dielectric spectroscopy (DS). The analysis of dielectric spectra in planar and homeotropic cells revealed the evolution of relaxation mechanisms, transitioning from single-particle molecular reorientations in the isotropic phase to complex collective dynamics across the nematic (N), intermediate (N X ), and ferroelectric nematic (N F ) phases. Critical soft-mode behavior was observed near the N F transition for both the longitudinal mode (m1, acting as an amplitude mode) and the high-frequency mode (m3, exhibiting phason-like characteristics), indicating strong coupling between molecular dipoles and splay fluctuations. Furthermore, fitting the dielectric permittivity to a modified Curie–Weiss law reveals a broad temperature range of relaxor-like behavior above T c, characterized by diffuseness exponents γ ≈1.6 for ferroelectric members ( 3JK,4JK). This confirms the formation of Polar Nanoregions (PNRs) stabilized by lateral shifted molecular arrangements in the high-temperature nematic liquid, establishing a nematic relaxor ferroelectric (nRFE) state spanning almost the entire N phase window.
Source: ChemRxiv
Language: English
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7223577561