Lattice dynamics and Raman spectrum of supertetragonal PbVO3

• Type: Article in International Scientific Journal
• Date: 2023

Authors

Bouvier, P (Author) Other; Sasani, A (Author) Other; Bousquet, E (Author) Other; Guennou, M (Author) Other; Agostinho Moreira, JA (Author) FCUP

Journal

Title: Journal of Physics and Chemistry of Solids

Vol. 173

ISSN: 0022-3697

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 1 Citation

Scopus - 1 Citation

Other information

Authenticus ID: P-00X-G38

DOI: 10.1016/j.jpcs.2022.111092

Abstract (EN): Lead vanadate PbVO3 is a polar crystal with a P4mm space group under ambient conditions. PbVO3 is isostructural with the model soft mode-driven ferroelectric PbTiO3, but it differs due to the so-called super-tetragonal elongation of its unit cell. In this study, we investigated the lattice dynamics of PbVO3 based on Raman spectroscopy at room temperature and first-principle calculations. All zone-center transverse optical phonon modes were identified by polarized, angle-dependent Raman spectroscopy and assigned as follows: E modes at 136, 269, 374, and 508 cm(-1); A(1) modes at 188, 429, and 874 cm(-1), and B-1 mode at 319 cm(-1). The calculations confirmed the experimental symmetry assignment and allowed us to obtain the longitudinal optical phonon wavenumbers. In addition, we analyzed the mode eigenvectors in detail in order to identify the atomic displacements associated with each mode and compare them with PbTiO3. Despite differences in chemistry and strain, the phonon eigenvectors were found to be highly comparable in both compounds. We investigated the position of the ferroelectric soft mode in PbVO3 compared with PbTiO3. Sizeable splitting of the B-1+E modes appeared as a characteristic feature of supertetragonal phases. The peculiarity of the vanadyl V-O bond frequency in PbVO3 was also addressed.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 10