Vibrational and thermodynamic properties of orthorhombic CaSnO3 from DFT and DFPT calculations

Abstract

a b s t r a c tDensity functional theory (DFT) and density functional perturbation theory (DFPT) calculations were used to investigate the vibrational and thermodynamic properties of orthorhombic stannate CaSnO 3 compound. Our approach was based on the generalized gradient approximation with dispersion correction (GGA þ D), considering the norm-conserved pseudopotentials. The phonon dispersion relation as well as theoretical peaks of the infrared (IR) and Raman spectrum in the frequency range of 100-800 cm À 1 was analyzed and assigned. The thermodynamic potentials and the specific heat at constant volume of the CaSnO 3 compound are also calculated, whose dependence with the temperature are discussed.

CaSnO 3 obtained by modified Pechini method applied in the photocatalytic degradation of an azo dye

“…The vibrations assigned to stannates (SnO 3 2-) generally produce highintensity bands in the infrared region at 300-400 cm -1 and 600-700 cm -1 with a band broadening typical of orthorhombic perovskite structures [27,32]. The mid-IR spectrum of CaSnO 3 showed a band at 641 cm -1 assigned to the stretching mode of Sn-O [33,34]. For the spectrum obtained in the far-IR range (inset of Fig.…”

“…For the spectrum obtained in the far-IR range (inset of Fig. 3), the bands at 362 and 390 cm -1 corresponded to the bending mode of O-Sn-O [34], while modes at 459 and 503 cm -1 were assigned to SnO 6 vibrations [32], and bands at 559 and 642 cm -1 referred to the stretching modes of Sn-O bonds [32,34].…”

Electronic structure, optical and dielectric properties of BaTiO3/CaTiO3/SrTiO3 ferroelectric superlattices from first-principles calculations

“…According to the literature [41][42][43][44] , the phonon properties can be obtained using a harmonic approximation by:…”

Thermal properties of the orthorhombic CaSnO3 perovskite under pressure from ab initio quasi-harmonic calculations

“…At ambient conditions, CaSnO 3 exhibits a orthorhombic GdFeO 3 -type perovskite structure belonging to the P bnm space group, which is expected to be stable up to pressures of about 40 GPa and temperatures of about 2000 K [25]. Other phases have been reported (ilmenite-like, hexagonal, rhombohedral, tetragonal and cubic) [26][27][28][29], the orthorhombic one remaining the most studied [30][31][32][33][34][35][36][37][38]. Many fundamental properties of this material, however, still have to be reliably determined, which is the case of its thermal properties (its thermal structural and elastic features, its thermodynamic behavior, etc.).…”