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arXiv · 1512.08340

Resonant carbon K-edge soft x-ray scattering from lattice-free heliconical molecular ordering: soft dilative elasticity of the twist-bend liquid crystal phase

Chenhui Zhu·Michael R. Tuchband·Anthony Young·Min Shuai·Alyssa Scarbrough·David M. Walba·Joseph E. Maclennan·Cheng Wang·Alexander Hexemer·Noel A. Clark
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Abstract

Resonant x-ray scattering shows that the bulk structure of the twist-bend liquid crystal phase, recently discovered in bent molecular dimers, has spatial periodicity without electron density modulation, indicating a lattice-free heliconical nematic precession of orientation that has helical glide symmetry. In situ study of the bulk helix texture for the dimer CB7CB shows an elastically-confined temperature-dependent minimum helix pitch, but a remarkable elastic softness of pitch in response to dilative stresses. Scattering from the helix is not detectable in the higher temperature nematic phase.

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Chenhui Zhu, Michael R. Tuchband, Anthony Young, Min Shuai, Alyssa Scarbrough, David M. Walba, Joseph E. Maclennan, Cheng Wang, Alexander Hexemer, Noel A. Clark. 2015-12-28. Resonant carbon K-edge soft x-ray scattering from lattice-free heliconical molecular ordering: soft dilative elasticity of the twist-bend liquid crystal phase. https://doi.org/10.1103/physrevlett.116.147803

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