Numerical simulations of Gaussian white noise and field-induced phase transition in bulk antiferroelectrics using parameters of ammonium dihydrogen phosphate

This paper presents phenomenological and numerical studies of Gaussian white noise and fieldinduced dynamical phase transitions in bulk antiferroelectrics (AFE), focusing on the delayed transition from AFE to ferroelectric (FE) states. The steady states of the AFE are formulated by applying the calculus of variations to the AFE thermodynamic potential, in the absense of external noise. Stochastic relaxation equations for the AFE are then derived using the Landau — Khalatnikov equation, where the AFE thermodynamic potential accounts for both Gaussian white noise and a sinusoidal time-dependent electric field. These equations are solved numerically using the stochastic fourth-order Runge — Kutta (SRK4) method. The results indicate that, for an applied field amplitude of 97% of the transition amplitude, additional Gaussian white noise with amplitudes < 8% of the applied field induces delayed AFE to FE phase transitions, with the time delay inversely proportional to the noise amplitudes.