Scanning pyroelectric microscopy revealing the spatial polarity distribution in topologically centric crystals of trans-4-chloro-4 '-nitrostilbene

Scanning pyroelectric microscopy (SPEM) was applied to investigate grown-in polarity in trans-4-chloro-40-nitrostilbene (CNS) single crystals. Sectors {011} and {01 (1) over bar} were scanned for cross sections perpendicular to the a-direction. A rotational analysis for {011}, {01 (1) over bar} faces was performed for a needle like crystal turned around the a- axis. All pyroelectric experiments confirm a bipolar grown-in state of polarity for sector involving the twofold axis b. These measurements agree with theoretical force field and stochastic calculations, predicting a bipolar state and a nearly identical extent of polarity for two different sectors.