Understanding the Pressure Effect on the Elastic, Electronic, Vibrational, and Bonding Properties of the CeScO₃Perovskite

Abstract

CeScO 3 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 CeScO 3 , 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 CeScO 3 . 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 CeScO 3 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.

Density-functional study of pressure-induced phase transitions and electronic properties of Zn2V2O7

“…The larger the volume the more compressible the phase, as expected. 38 From Fig. 5 it can be seen that the transition from the γ-phase to the κ- and δ-phase involve a large volume collapse.…”

Theoretical calculations of the effect of nitrogen substitution on the structural, vibrational, and electronic properties of wolframite-type ScTaO4at ambient conditions

“…6). Here, we have used a value of U = 4.57 eV for Sc-d, 14 and for each concentration of nitrogen substitution, we have varied the U from 1.2 to 2 eV for the N-2p atom. 43 Notably, the attempt to apply such a correction leads to varying the position of 2p-N states of the minority spin channel into the valence band.…”

“…Due to our success in treating the d orbitals of the scandium atom in other oxides, 14 we have carried out the present calculations by means of a full-potential linearized augmented plane wave (FP-LAPW) implemented in the Wien2k package. 13 The generalized-gradient approximation (GGA) was used for the description of the exchange–correlation energy within the PBEsol prescription.…”

Enhancement of optoelectronic properties of layered MgIn$$_{2}$$Se$$_{4}$$ compound under uniaxial strain, an ab initio study

“…We also resorted to the use of semi-local functional, Perdew–Burke–Ernzerhof revised for solids (GGA-PBEsol) [ 48 ] exchange potential. This setup has been successfully used for the prediction of structural properties [ 30 ]. To achieve reliable accuracy calculations, the PREC tag, and other cutoff energies were chosen adequately.…”

“…Or alternatively, by introducing vacancies [ 27 , 28 ]. However, it is also possible to tune their electronic and optical properties as well as the photoresponse one by applying pressure [ 29 , 30 ].…”