Superlattice-induced ferroelectricity in charge-ordered La<sub>1/3</sub>Sr<sub>2/3</sub>FeO<sub>3</sub>.
basic_science · Level V
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- Record sourced from PubMed, PMID 31712434.
- Also identified by DOI 10.1073/pnas.1906513116 and PMC identifier 6883826.
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Abstract
Charge-order-driven ferroelectrics are an emerging class of functional materials, distinct from conventional ferroelectrics, where electron-dominated switching can occur at high frequency. Despite their promise, only a few systems exhibiting this behavior have been experimentally realized thus far, motivating the need for new materials. Here, we use density-functional theory to study the effect of artificial structuring on mixed-valence solid-solution La<sub>1/3</sub>Sr<sub>2/3</sub>FeO<sub>3</sub> (LSFO), a system well studied experimentally. Our calculations show that A-site cation (111)-layered LSFO exhibits a ferroelectric charge-ordered phase in which inversion symmetry is broken by changing the registry of the charge order with respect to the superlattice layering. The phase is energetically degenerate with a ground-state centrosymmetric phase, and the computed switching polarization is 39 μC/[Formula: see text], a significant value arising from electron transfer between [Formula: see text] octahedra. Our calculations reveal that artificial structuring of LSFO and other mixed valence oxides with robust charge ordering in the solid solution phase can lead to charge-order-induced ferroelectricity.