相关论文: Ab-initio studies on the phonons of BaTiO3 polytyp…

We report our first-principles investigations on three polytypes of BaTiO3 (BTO): a paraelectric phase with cubic Pm-3m structure and two ferroelectric (FE) phases with tetragonal P4mm and rhombohedral R3m structures. We compared the…

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…

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…

Multiferroics possess two or more switchable states such as polarization, magnetization, etc. Phonon excitations in multiferroic phase are strongly modified by magnetoelectric coupling, spin-phonon coupling, and anharmonic phonon-phonon…

Dielectric tensor and lattice dynamics of alpha-PbO2-type TiO2 have been investigated using the density functional perturbation theory, with a focus on responses of the vibrational frequencies to pressure. The calculated Raman spectra under…

BaTiO3 is a classical ferroelectric studied for last one century for its ferroelectric properties. Lattice dynamics of BaTiO3 is crucial as the utility of devices is governed by phonons. In this work, we show that traditional…

The sequence of phase transitions in PbHf0.83Sn0.17O3 has been studied by THz, far infrared and Raman spectroscopies, revealing the complementary behaviour of both, polar and non-polar phonons and their impact on the transition lattice…

EuTiO3 (ETO) has recently experienced an enormous revival of interest because of its possible multiferroic properties which are currently in the focus of research. Unfortunately ETO is an unlikely candidate for enlarged multifunctionality…

We have investigated the phonon and the magnetic excitations in LaCoO3 by inelastic neutron scattering measurements. The acoustic phonon dispersions show some characteristic features of the folded Brillouin zone (BZ) for the rhombohedrally…

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…

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…

Structural stability of paramagnetic (PM) body-centered cubic (bcc) Fe under pressure is investigated based on first-principles phonon calculations. Spin configurations of the PM phase are approximated using a binary special quasi-random…

Despite the technological significance of the tetragonal PbTiO3 for the piezoelectric transducer industry, its high pressure behaviour is quite controversial as two entirely different scenarios, involving pressure induced (1) morphotropic…

In this study, we investigate the formation of electron and hole small polarons in the prototypical ferroelectric material BaTiO3, with a focus on their interaction with ferroelectric distortive fields. To accurately describe the…

In a recent article, Gr\"{u}nebohm et al. [Phys. Rev. B 84 132105 (2011), arXiv:1106.2820] report that they fail to reproduce the A2u ferroelectric instability of TiO2 in the rutile structure calculated with density functional theory within…

A first-principles study of the vibrational modes of PbTiO_3 in the ferroelectric tetragonal phase has been performed at all the main symmetry points of the Brillouin zone (BZ). The calculations use the local-density approximation and…

We investigate the binding surface along the Bain path and phonon dispersion relations for the cubic phase of the ferromagnetic binary alloys Fe3X (X = Ni, Pd, Pt) for L12 and DO22 ordered phases from first principles by means of density…

We report on TmMnO3 far infrared emissivity and reflectivity spectra from 1910 K to 4 K. At the highest temperature the number of infrared bands is lower than that predicted for centrosymmetric P63/mmc (D6h4) (Z=2) space group due high…

High pressure x-ray diffraction (XRD) measurements on RMnO3 (R=Dy, Ho and Lu) reveals that varying structural changes occurs for different R ions. Large lattice changes (orthorhombic strain) occur in DyMnO3 and HoMnO3 while the Jahn-Teller…

We determine the nature of coupled phonons and magnetic excitations in AlFeO3 using inelastic light scattering from 5 K to 315 K covering a spectral range from 100-2200 cm-1 and complementary first-principles density functional theory-based…