Fig. 3

Spontaneous chiral symmetry breaking for 8CB on circular posts. POM images of 8CB on a 0.2 μm and b 2.0 μm posts at various temperatures. Both samples were slowly heated (1 °C/min) from smectic phase to nematic phase. c Schematic of the smectic layers adopted by 8CB on top of a SU8 post, forming a toroidal focal conic domain (TFCD). Within a TFCD, radial in-plane LC director is strongly imposed. d Frequency histograms of quantitative chirality measurements for 8CB at 34 °C in the nematic phase over 40 posts. The magnitude of the chirality is influenced by the post height, such that short posts induce greater chiral symmetry breaking. e–g Simulated POM images of 8CB alignment at 34 °C as a function of saddle-splay constant (\({K}_{24}/{K}_{22}\)) and SU8 surface anchoring strength. Blue dash boxes indicate structures consistent with experiment as described in the main text; the intersection of these three regions is highlighted in red