Energy dependence of resonant x-ray scattering for the twist bend nematic phase, a helix of liquid crystals

ORAL

Abstract

We examined the manifestation of resonance effects in twist bend nematic (NTB), smectic A (SmA) and crystalline phases via tender resonant X-ray scattering (TReXS) at sulfur K-edge. While SmA layering peak is partially resonant, scattering peak of NTB is purely resonant visible only near S K-edge. The difference is attributed to the periodic molecular orientation variation with weak electron density modulation. We further demonstrate that the energy-dependence of such scattering peak arising from pure orientation variation scales with the sum of f1(E)^2 and f2(E)^2, corresponding to the real and imaginary parts of dispersion correction respectively, while the resonant contribution in sulfur-containing SmA scales with f1(E), and is a first order perturbation to the relatively strong non-resonant peak from electron density modulation.

*Director of the Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under contract no. DE-AC02-05CH11231. The work was also supported by National Natural Science Foundation of China (No. 21774099, 21761132033 and 51603166), Science and Technology Agency of Shaanxi Province (2016KW-050 and 2018KWZ-03). Y.C. also thanks China Scholarship Council (CSC) for providing financial support (201706280170).

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Presenters

  • Chenhui Zhu

    • ANL
    • Advanced Light Source, Lawrence Berkeley National Laboratory

Authors

  • Yu Cao

    • State Key Laboratory for Mechanical Behavior of Materials, Shaanxi International Research Center for Soft Matter, School of Materials Science and Engineering, Xi'an Jiaotong

  • Jun Feng

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

  • Asritha Nallapaneni

    • University of Akron
    • Department of Polymer Engineering, University of Akron

  • Yuki Arakawa

    • Department of Applied Chemistry and Life Science, Toyohashi University of Technology

  • Keqing Zhao

    • College of Chemistry, Sichuan Normal University

  • Feng Liu

    • State Key Laboratory for Mechanical Behavior of Materials, Shaanxi International Research Center for Soft Matter, School of Materials Science and Engineering, Xi'an Jiaotong

  • Chenhui Zhu

    • ANL
    • Advanced Light Source, Lawrence Berkeley National Laboratory