The interplay between spatial and heliconical bond order in twist-bend nematic materials

ORAL

Abstract

The nanostructure of two novel sulfur containing dimer materials have been investigated
experimentally by hard and by resonant tender X-ray scattering techniques. We find that below the nematic (N) to NTB transition the positional correlations drop significantly, while the bond-order correlations increase from zero to about 60 nm. The temperature dependences of the heliconical pitch show stronger variation neat the N-NTB transition that the CBnCB-type dimers. The heliconical pitch is observable even in the upper 3-4°C range of the underlying smectic phase. The coexistence of the smectic order and the heliconical order indicates a SmCTB -type phase where the rigid units of the dimers are tilted with respect to the layer normal to allow for the bending of the dimers, but the tilt direction rotates following the heliconical order.

*This research was supported by the National Science Foundation under grant DMR-1904167 and by (UK) EPSRC project EP/M015726/1. We acknowledge use of Beamlines 7.3.3 and 5.3.1 of the Advanced Light Source supported by the Director of the Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under contract no. DE-AC02-05CH11231.

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Presenters

  • Rony Saha

    • Kent State University
    • Department of Physics, Kent State University

Authors

  • Rony Saha

    • Kent State University
    • Department of Physics, Kent State University

  • Chenrun Feng

    • Kent State University
    • Advanced Materials and Liquid Crystal Institute, Kent State University

  • Christopher Welch

    • Chemistry, University of Hull

  • Georg H. Mehl

    • Chemistry, University of Hull

  • Jun Feng

    • Lawrence Berkeley National Lab
    • Lawrence Berkeley National Laboratory

  • Chenhui Zhu

    • Advanced Light Source, Lawrence Berkeley National Lab
    • Lawrence Berkeley National Laboratory
    • Lawrence Berkeley National Lab
    • Advanced Light Source, Lawrence Berkeley National Laboratory

  • James Gleeson

    • Kent State University

  • Samuel N Sprunt

    • Kent State University
    • Department of Physics, Kent State University

  • Antal Istvan Jakli

    • Kent State University
    • Advanced Materials and Liquid Crystal Institute, Kent State University