Related papers: Phonon Properties of Knbo3 and Ktao3 from First-Pr…
{}From a series of total energy calculations by the full-potential linear muffin-tin orbital method, the total energy hypersurface as function of atomic displacements from equilibrium positions has been fitted for different Gamma phonon…
The four A1-TO Gamma phonon frequencies in lithium tantalate are calculated in the frozen-phonon approach from first principles using the full-potential linearized augmented plane wave method. A good agreement with the experimental data…
The equilibrium ground-state structure of LiNbO3 in the paraelectric and ferroelectric phases is fully optimized in a first-principles calculation using the full-potential linearized augmented plane wave method. The equilibrium volume, c/a…
The atomic, electronic structure and phonon frequencies have been calculated in a cubic and low-temperature tetragonal SrTiO3 phases at the ab initio level. We demonstrate that the use of hybrid exchange-correlation PBE0 functional gives…
In order to arrive at ultimately accurate results available with the LMTO method in the local density approximation, the stability of full-potential LMTO predictions for off-center displacements in KNbO3, as depending on the choice of basis…
Phonon frequencies at Gamma-point in non-magnetic rhombohedral phase of LaCoO3 were calculated using density functional theory (DFT) with hybrid exchange correlation functional PBE0. The calculations involved a comparison of results for two…
The lattice dynamics of the $\rm YMnO_3$ magneto-electric compound has been investigated using density functional calculations, both in the ferroelectric and the paraelectric phases. The coherence between the computed and experimental data…
Phonon frequencies at {\Gamma},X,M,R-points of Brilloin zone in cubic phase of Ba(Ti,Zr,Hf)O3 were first time calculated by frozen phonon method using density functional theory (DFT) with hybrid exchange correlation functional PBE0. The…
Group theoretical aspects of the three temperature-dependent and temperature-reversible experimentally observed phase transitions in the KNbO3 crystal (cubic-tetragonal, tetragonal-orthorhombic, orthorhombic-rhombohedral) in the framework…
Temperature-dependent Raman spectra of TbMnO$_3$ from 5 K to 300 K in the spectral range of 200 to 1525 cm$^{-1}$ show five first-order Raman allowed modes and two high frequency modes. The intensity ratio of the high frequency Raman band…
The quantum corrections to the frequencies of the $\Gamma$ point longitudinal optical (LO) and transverse optical (TO) phonon modes in carbon nanotubes are investigated theoretically. The frequency shift and broadening of the TO phonon mode…
KTaO$_3$ (KTO) is an incipient ferroelectric, characterized by a softening of the lowest transverse optical (TO) mode with decreasing temperature. Cooper pairing in the recently discovered KTO-based heterostructures has been proposed to be…
Understanding surface collective dynamics in quantum materials is crucial for advancing quantum technologies. For example, surface phonon modes in quantum paraelectrics are thought to play an essential role in facilitating interfacial…
The lattice dynamics of TiO$_2$ in the rutile crystal structure was studied by a combination of thermal diffuse scattering, inelastic x-ray scattering and density functional perturbation theory. We experimentally confirm the existence of an…
The infrared (IR) reflectivity spectra of orthorhombic manganese perovskites PrMnO$_3$ and CaMnO$_3$ are studied in the frequency range of optical phonon modes at temperatures varying from 300 to 4 K. The IR phonon spectra of these two…
Using first-principles calculations, the phonon frequencies at the $\Gamma$ point and the dielectric tensor are determined and analysed for the cubic and rhombohedral phases of BaTiO$_{3}$. The dipole-dipole interaction is then separated…
Understanding collective phenomena in quantum materials from first principles is a promising route toward engineering materials properties on demand and designing new functionalities. This work examines the quantum paraelectric state, an…
In this study, we present a comprehensive analysis of the Raman active phonon modes in orthorhombic LaInO$_3$ based on a combination of polarization-angle resolved Raman spectroscopy and density functional theory calculations. By using…
We have performed Raman scattering measurements on BiFeO3 nanoparticles and studied both magnetic and lattice modes. We reveal strong anomalies between 140 K and 200 K in the frequency of magnon and E(LO1), E(TO1) and A1(LO1) phonon modes.…
The dynamic structures of the cubic and tetragonal phase in BaTiO3 and its dielectric response above the cubic-to-tetragonal phase transition temperature (Tp) are studied by first-principles molecular dynamics (MD) simulation. It's shown…