Improper ferroelectricity and piezoelectric responses in rhombohedral (A,A′)B2O6perovskite oxides

Abstract

High-temperature electronic materials are in constant demand as the required operational range for various industries increases. Here we design (A,A )B 2 O 6 perovskite oxides with [111] "rock salt" A-site cation order and predict them to be potential high-temperature piezoelectric materials. By selecting bulk perovskites which have a tendency towards only out-of-phase BO 6 rotations, we avoid possible staggered ferroelectric to paraelectric phase transitions while also retaining noncentrosymmetric crystal structures necessary for ferro-and piezoelectricity. Using density functional theory calculations, we show that (La,Pr)Al 2 O 6 and (Ce,Pr)Al 2 O 6 display spontaneous polarizations in their polar ground state structures; we also compute the dielectric and piezoelectric constants for each phase. Additionally, we predict the critical phase transition temperatures for each material from first-principles to demonstrate that the piezoelectric responses, which are comparable to traditional lead-free piezoelectrics, should persist to high temperature. These features make the rock salt A-site-ordered aluminates candidates for high-temperature sensors, actuators, or other electronic devices.

Magneto-electric multiferroics: designing new materials from first-principles calculations

“…This mechanism is identical to that previously established by Young and Rondinelli in 2014 in (111)oriented (RAlO3)1/((PrAlO3)1 superlattices with R=La or Ce, i.e. superlattices based on non-polar materials adopting a R-3c structure 127 . Finally, ABO3 improper ferroelectrics with a coupling between and another non-polar motion remains scarce and to the best of our knowledge, these ABO3 improper ferroelectrics have so far only involved hexagonal systems.…”

Understanding ferroelectricity in layered perovskites: new ideas and insights from theory and experiments

“…3b), there is no combination of octahedral rotations that will lift inversion symmetry. This was shown using representation theory and supported by first-principles calculations on gallate, zirconate, and hafnate superlattices 97 (note that if B cation ordering is included, this restriction is lifted). Double perovskites with the AA′BB′O 6 stoichiometry tend to exhibit layered ordering of the A and A′ cations and rocksalt ordering of the B and B′ (Fig.…”

Designing new ferroelectrics with a general strategy

“…Note that the A-site order in the 1:1 superlattice exhibits the non-FE structure with the R32 symmetry. 28 In the following, LaCoO 3 and LaAlO 3 are selected as the parent structures to demonstrate the B-site substitution induced ferroelectricity in the R3c ABO 3 perovskites. It was experimentally known that LaCoO 3 and LaAlO 3 take the R3c structure as the ground state, which is also confirmed by our test calculations.…”

“…If we consider a twofold 20-atom supercell, there are 3 types ferroelectrics which result from the Asite, B-site and C-site substitutions, respectively [see Fig S5 (a), (b) and (c) for A-site, B-site and C-site substitutions, respectively]. Note that the A-site order in the 1:1superlattice exhibits a non-FE structure with the R32 symmetry[34].In the following, LaCoO3 and LaAlO3 are selected as the parent structures to demonstrate the B-site substitution induced ferroelectricity in the 𝑅3 ̅ 𝑐 ABO3 perovskite. The mismatch in the lattice constants between these two compounds is only about 0.13%.…”