Ferroelectricity, nonlinear dynamics, and relaxation effects in monoclinic Sn2P2S6.
An ab initio-based model of the temperature-induced ferroelectric phase transition in Sn2P2S6 (SPS) as a prototype of an unconventional ferroelectric is developed. The order parameter in SPS is found as the valley line on a total-energy surface of the zone-center fully symmetrical Ag and polar Bu distortions. Significant nonlinear coupling between order parameter and strain is observed. Monte Carlo simulations describe the additional low-temperature rearrangement in polar structure, which appears in domain boundaries, and describe the relaxation phenomena near the ferroelectric phase transition.
Rushchanskii
Konstantin Z
KZ
Institute for Solid State Physics and Chemistry, Uzhgorod National University, 54 Voloshyn St., 88000 Uzhgorod, Ukraine.
Vysochanskii
Yulian M
YM
Strauch
Dieter
D