Revealing the antipolar order in the antiferroelectric SmZA phase by means of circular alignment
Journal article, 2024

Many ferroelectric nematic liquid crystals, like one of the archetype materials, DIO, do not have a direct paraelectric N to ferroelectric NF phase transition, but exhibit yet another phase between N and NF. This phase has recently been proposed to be antiferroelectric, with a layered structure of alternating polarization normal to the average director and is sometimes referred to as Smectic ZA (SmZA). We have examined the SmZA phase in circularly rubbed (CR) cells, known to discriminate between the polar NF and the non-polar N phase from the configuration of disclination lines formed. We find that the ground state of SmZA has the same disclination configuration as the non-polar N phase, demonstrating that the SmZA phase is also non-polar, i.e., it has no net ferroelectric polarization. At the same time, the SmZA texture generally has a grainy appearance, which we suggest is partly a result of the frustration related to layered order combined with the imposed twist in CR cells. We discuss possible orientations of the smectic layers, depending on the alignment conditions. While a horizontal SmZA layer structure is always compatible with surface-induced twist, a vertical layer structure would tend to break up in a twisted bookshelf structure to match non-parallel alignment directions at the two surfaces.

Author

Pierre Nacke

University of Stuttgart

Rachel Tuffin

Merck KGaA

Melanie Klasen-Memmer

Merck KGaA

Per Rudqvist

Chalmers, Microtechnology and Nanoscience (MC2), Electronics Material and Systems

F. Giesselmann

University of Stuttgart

Scientific Reports

2045-2322 (ISSN) 20452322 (eISSN)

Vol. 14 1 15018

Ferroelectric nematic liquids

Swedish Research Council (VR) (2023-04853), 2024-01-01 -- 2027-12-31.

Subject Categories

Condensed Matter Physics

DOI

10.1038/s41598-024-65275-y

PubMed

38951542

More information

Latest update

8/8/2024 1