Antiferroelectricity with metastable polar state from Kittel model

Abstract

We have revisited the Kittel model that describes antiferroelectricity (AFE) in terms of two sublattices of spontaneous polarization with antiparallel couplings. By constructing the comprehensive phase diagram including the antiferroelectric, ferroelectric, and paraelectric phases in the parameter space, we identified an AFE phase with stable antipolar states and metastable polar state (SAMP) due to the weak coupling between sublattices. We found that the metastability of the polar state in SAMP phase could lead to apparent remanent polarization, depending on the measurement timescale. This explains the observed ferroelectric behavior of orthorhombic hafnia, which is predicted to be antipolar by density functional theories.