Turning ABO$_3$ antiferroelectrics into ferroelectrics: Design rules for practical rotation-driven ferroelectricity in double perovskites and A$_3$B$_2$O$_7$ Ruddlesden-Popper compounds

摘要

Ferroic transition metal oxides, which exhibit spontaneous elastic,electrical, magnetic or toroidal order, exhibit functional properties that finduse in ultrastable solid-state memories to sensors and medical imagingtechnologies. To realize multifunctional behavior, where one order parametercan be coupled to the conjugate field of another order parameter, however,requires a common microscopic origin for the long-range order. Here, weformulate a complete theory for a novel form of ferroelectricity, whereby aspontaneous and switchable polarization emerges from the destruction of anantiferroelectric state due to octahedral rotations and ordered cationsublattices. We then construct a materials design framework based oncrystal-chemistry descriptors rooted in group theory, which enables the faciledesign of artificial oxides with large electric polarizations, P, simultaneouswith small energetic switching barriers between +P and -P. We validate thetheory with first principles density functional calculations on more than 16perovskite-structured oxides, illustrating it could be operative in anymaterials classes exhibiting two- or three-dimensional corner-connectedoctahedral frameworks. We show the principles governing materials selection ofthe "layered" systems originate in the lattice dynamics of the A cationdisplacements stabilized by the pervasive BO$_6$ rotations of single phaseABO$_3$ materials, whereby the latter distortions govern the optical band gaps,magnetic order and critical transition temperatures. Our approach provides theelusive route to the ultimate multifunctionality property control by anexternal electric field.