Heliconical-fluctuation-induced compensation point in the diluted cholesteric phase of mixtures containing the flexible dimer CB7CB

Patrick Oswald (1) , Alain Dequidt (2)

1 Phys-ENS - Laboratoire de Physique de l'ENS Lyon
2 ICCF - Institut de Chimie de Clermont-Ferrand

We show experimentally and theoretically that the heliconical fluctuations that develop in a cholesteric phase (Ch) close to a transition to a chiral twist-bend nematic phase (NTB) may lead to the appearance of a compensation point. At this point, the equilibrium twist of the cholesteric phase vanishes and changes sign. Mixtures of the flexible dimer CB7CB and the rod-like molecules 8CB or 5CB, doped with a small amount of the chiral molecules R811, S2011, CC or CB15, are used in experiments to determine the conditions for the appearance of a compensation point.

Mots clés: numbers: 61-30.Eb; 61-30.Dk; 62.25.-g

Domaines: Physique [physics]; Matière Condensée [cond-mat]

Patrick Oswald, Alain Dequidt. Heliconical-fluctuation-induced compensation point in the diluted cholesteric phase of mixtures containing the flexible dimer CB7CB. Physical Review E , 2022, 105 (2), pp.024707. ⟨10.1103/PhysRevE.105.024707⟩. ⟨hal-03616332⟩