Potential ferroelectricity in charge-transfer organic materials is often masked by the intrinsic
conductivity. Here, we report the compelling evidence of ferroelectricity in organic π-
conjugated meta-nitroaniline (m-NA) crystals as shown by the local electromechanical
measurements using the piezoresponse force microscopy (PFM) technique. m-NA is a
charge-transfer molecular material with the exceptional optical non-linearity and perceptible
conductivity along the crystallographic polar axis. While standard Sawyer-Tower …