Figure 1

(a) Molecular structure of the NG126 compound. The principal axes (u,v,w) of the susceptibility tensor $\chi$ of one sulfur atom are shown. A schematic representation of the bent-core molecules (P is the polarization direction) is displayed. (b) Model for the $B_1$ structure proposed in Ref. [14] showing its orientation with respect to the glass substrate. (c) Structure of the $B_1$ phase deduced from nonresonant scattering. (d) Resonant diffraction diagram for the structure in (b). The set of solid circles is the nonresonant diagram and the open circles are the reflections of resonant nature. The sizes of the dots indicate the relative intensities and the dashed line the experimentally accessible region. (e) Geometry of the diffraction experiment.Reuse & Permissions

Figure 2

(a), (b) Proposed models for the polarization periodicity in a columnar structure together with their resonant diffraction diagrams. The dashed line indicates the experimentally accessible region. The orange dot represents the origin of the reciprocal lattice. (c) Alternative model for which resonant reflections should be observed on the dashed line.Reuse & Permissions

Figure 3

(a) Resonant reflections observed in the $B_2$ phase (full circles) and in the $B_1$ phase (open squares). In both cases the reflection is centered at $Q=(3/2)Q\left(002\right)$. The beam energy was 2.4728 keV. The inset shows a typical rocking curve of the $\left(002\right)$ nonresonant reflection. (b) Azimuth of the scattered radiation for the resonant peak in the $B_2$ phase as a function of the sample orientation angle φ. The full circles are experimental results and the thick line is the best fit. Dashed line corresponds to the Sm-$C_A$P${}_A$ phase. Thin line corresponds to a perfect monodomain Sm-$C_S$P${}_A$ sample with $\alpha ={54}^{°}$. The scheme represents a molecule within a $B_2$ layer, where the orientation of the eigenvectors $u$,$v$,$w$ is not symmetry restricted as in Fig. 1(a).Reuse & Permissions