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Understanding the Pressure Effect on the Elastic, Electronic, Vibrational, and Bonding Properties of the CeScO3 Perovskite

Abstract: CeScO3 is a promising perovskite-type material that presents the characteristic to remain highly stable upon compression, contrary to other perovskite compounds that often undergo phase transformations under pressure. In contrast with the structural behavior of CeScO3, the influence of pressure on other of its physical properties, such as electronic, vibrational, atomic, and polyhedral bulk and elastic properties, is still unknown. In this work, we propose to fill this gap by a combination of computational quantum-mechanics methodologies based on density-functional theory (DFT) and high-pressure Raman spectroscopy experiments. In particular, the influence of pressure in the crystal structure has been studied, up to 40 GPa, and compared with previous experiments showing that DFT properly describes the changes induced by pressure in CeScO3. Calculations have also been used to obtain phonon frequencies and their pressure dependence and to propose a mode-symmetry assignment. From Raman experiments, we have obtained the frequency and pressure dependence of lattice vibrations involving changes in polarizability, validating phonon calculations, which give not only Raman-active but also infrared-active and silent modes. In addition, phonon-dispersion and elastic-constant calculations are consistent with the structural stability of an orthorhombic perovskite-type up to 40 GPa. Finally, we provide a description of the electronic band structure, showing that CeScO3 has a much smaller band gap than other scandates because of the role of Ce f-electrons. Such electrons also cause a closing of the electronic band gap under compression.

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 Fuente: J. Phys. Chem. C 2021, 125, 1, 107-119

Editorial: American Chemical Society

 Año de publicación: 2021

Nº de páginas: 13

Tipo de publicación: Artículo de Revista

ISSN: 1932-7447,1932-7455

Proyecto español: PID2019-106383GB-C41; RED2018-102612-T ; PGC2018-094814-BC22

Url de la publicación: https://doi.org/10.1021/acs.jpcc.0c08641

Autores/as

OUAHRANI, TARIK

MEDJDOUB,FATIMA-ZOHRA

GUEDDIDA, SABER

LOBATO FERNANDEZ, ÁLVARO

FRANCO, RUTH

BENKHETTOU, NOUR-EDDINE

BADAWI, MICHAEL

LIANG, AKUN

ERRANDONEA, DANIEL