Piezoelectric properties of ferroelectric perovskite superlattices with polar discontinuity
Abstract
The stability of a highsymmetry $P4mm$ polar phase in seventeen shortperiod ferroelectric perovskite superlattices with polar discontinuity is studied from first principles within the densityfunctional theory. It is shown that in most superlattices this phase exhibits either the ferroelectric instability or the antiferrodistortive one, or both of them. For each superlattice, the groundstate structure, the structure of possible metastable phases, the spontaneous polarization, and piezoelectric properties are calculated. The properties of superlattices with the polar discontinuity are compared with those of superlattices with broken symmetry and of ordinary superlattices, which have no the polar discontinuity. It is shown that high piezoelectric coefficients (up to 150270 pC/N) in some superlattices with the polar discontinuity are due to the appearance of strong lattice distortions, whose symmetry follows that of a lowlying polar phonon mode of the groundstate structure, under the influence of external strain.
 Publication:

arXiv eprints
 Pub Date:
 December 2020
 arXiv:
 arXiv:2012.08817
 Bibcode:
 2020arXiv201208817L
 Keywords:

 Condensed Matter  Materials Science;
 Condensed Matter  Mesoscale and Nanoscale Physics
 EPrint:
 13 pages, 4 figures, 5 tables