Nature of Modulated Structure of K2ZnCl4in Ferroelectric Phase

Distribution of the X-ray Bragg reflections in the reciprocal space was investigated for K 2 ZnCl 4 at room temperature by means of the Weissenberg method. The structure in the ferroelectric phase is interpreted as a modulated structure, with a tripled c -axis if the unmodulated high-temperature structure, induced predominantly by a transverse phase modulation polarized along the ferroelectric a -axis. The atomic displacements due to the modulated waves are estimated from the crystal structure determined by Mikhail and Peters.