Electron-lattice coupling contributions to polarization switching in charge-order-induced ferroelectrics

Abstract

We carry out first-principles density-functional-theory calculations to elucidate the polarization switching mechanism in charge-ordering-induced ferroelectrics based on the prototypical case of the (SrVO${}_3$)${}_1$(LaVO${}_3$)${}_1$ superlattice. We find that lattice relaxation for a specific charge ordering state can "lock" that state in, making non-adiabatic switching to a different CO variant energetically prohibitive, and in some cases, even making the energy barrier for adiabatic switching prohibitively large. We classify charge-ordering materials into two types, polyhedral breathing and off-centering displacement, based on the type of lattice mode most strongly coupled to the charge ordering. We demonstrate that the non-adiabatic electron hopping induced by an external electric field is expected only in off-centering-displacement-type charge-ordering-induced ferroelectrics. This successfully explains the different observed switching behaviors of LuFe${}_2$O${}_4$ and Fe${}_3$O${}_4$. These results offer a new understanding of the polarization switching mechanism in charge-ordering-induced ferroelectrics that provides guidance for the design and discovery of charge-ordering-induced ferroelectric materials and suggests a strategy for realizing "electronic ferroelectricity" with polarization switching on electronic rather than lattice time scales.

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Cited by in corpus (3)

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• Phonon anomalies within the polar charge density wave phase of the structurally chiral superconductor Mo${}_3$Al${}_2$C
• Elastic stripes formation at electronic transitions