engleski

Temperature Dependence of the Birefringence and the Electroclinic Effect in the Twist-Bend Nematic Phase

The recently discovered twist-bend nematic (NTB) phase [1] has attracted much attention with its spontaneous bend of the director field and its heliconical structure with a doubly degenerate chirality. Despite the sustained experimental and theoretical investigation of newly synthesized NTB materials, the main structural characteristics (the pitch, p, and the conical angle, q) and elastic properties of the phase have yet rarely been determined. Here we study experimentally the temperature dependence of the birefringence and the ECE(NTB) response in three different NTB materials, the bimesogens. We compare the experimental dependences of q(T) and p(T) with the theoretically predicted behavior. The agreement of the experimental results with the theory is only qualitative, suggesting the need to improve further the theoretical models.

twist-bend nematic phase ; homeotropic alignment ; birefringence ; electroclinic effect

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