Diffuse Scattering, Short Range Order and Nanodomains in the Paraelectric SbSI

Abstract

The ferroelectric crystal structure of SbSI is built of [Sb(S,I)]∞ chains parallel to [001] axis. In the paraelectric phase the crystal structure is disordered. Each atom is shifted from the xy mirror plane by Δ z up or down along [001]. The Reverse Monte Carlo (RMC) simulation of diffuse scattering revealed a complicated picture of the short and medium range order. The chains are not uniform but consist of sections of different length and opposite polarity. The distribution of these sections revealed by RMC shows irregular positively or negatively polarized nanodomains. The nanodomains about 0.5 nm thick, 2.0 broad and a few nm long are elongated in the [001] direction.