Shell model analysis of the low-energy lattice dynamics in PbHfO₃

Abstract

Antiferroelectric-based crystals are key ingredients of modern piezoelectric and optoelectronic materials as well as materials for applications in energy storage and nonvolatile memory devices. Nanoscale modulated phases are commonly found in antiferroelectrics doped with a small concentration of ferroelectric material. Lattice dynamics in the paraelectric phase of antiferroelectrics provides an important tool for assessing the mechanisms of formation of modulated phases. We present here the results of the analysis of the phonon spectra of the antiferroelectric perovskite lead hafnate in the frames of the shell model and show that a highly anisotropic polarizability of oxygen may play an important role in conditioning the tendency towards the nanoscale modulations.

KEYWORDS:

• Antiferroelectric
• PbHfO₃
• lead hafnate
• lattice dynamics
• shell model

Funding

R. Burkovsky acknowledges the support by Grant of the President of Russian Federation for state support of Russian young scientists MK-5685.2016.2. D. Andronikova and Yu. Bronwald acknowledge the support of RFBR (grant 16-02-01162, 16-32-00591). The work of Yu. Bronwald and A. Filimonovwas performed under the government order of the Ministry of Education and Science of RF.