Charge-order-induced ferroelectricity in LaVO$_{3}$/SrVO$_{3}$ superlattices

TL;DR

This study demonstrates that LaVO$_{3}$/SrVO$_{3}$ superlattices can exhibit charge-order-induced ferroelectricity due to layered charge and cation ordering, with potential for electric field-induced switching.

Contribution

First-principles calculations reveal a polar, ferroelectric-like phase in LaVO$_{3}$/SrVO$_{3}$ superlattices driven by charge ordering, a novel mechanism for ferroelectricity in these materials.

Findings

Layered charge ordering produces spontaneous polarization.

Polar state is close in energy to the nonpolar ground state.

Tensile strain can induce or enhance ferroelectricity.

Abstract

The structure and properties of the 1:1 superlattice of LaVO$_{3}$ and SrVO$_{3}$ are investigated with a first-principles density-functional-theory-plus-$U$ (DFT+$U$) method. The lowest energy states are antiferromagnetic charge-ordered Mott-insulating phases. In one of these insulating phases, layered charge ordering combines with the layered cation ordering to produce a polar structure with nonzero spontaneous polarization normal to the interfaces. This polarization is produced by electron transfer between the V$^{3+}$ and V$^{4+}$ layers, and is comparable to that of conventional ferroelectrics. The energy of this polar state relative to the nonpolar ground state is only 3 meV per vanadium. Under tensile strain, this energy difference can be further reduced, suggesting that the polar phase can be induced by applied electric field, yielding an antiferroelectric double-hysteresis loop. If the system does not switch back to the nonpolar state on removal of the field, a ferroelectric-type hysteresis loop could be observed.