Related papers: First Principles Calculations of Ionic Vibrational…
Lattice dynamics for five ordered PMN supercells were calculated from first principles by the frozen phonon method. Maximal symmetries of all supercells are reduced by structural instabilities. Lattice modes corresponding to these…
Ab initio phonon calculations for the nonpolar reference structures of the (001), (110), and (111) PbZrO_3/PbTiO_3 [1:1] superlattices are presented. The unstable polar modes in the tetragonal (001) and (110) structures are confined in…
We apply standard, first-principles calculations to a complete treatment of lattice dynamics in the harmonic approximation. The algorithm makes use of the straightforward ``frozen-phonon'' approach to the calculation of vibrational spectra…
Using first-principles calculations based on a variational density functional perturbation theory, we investigate the lattice dynamics of solid solutions of barium and strontium titanates. Averaging the information available for the related…
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…
An accurate and easily extendable method to deal with lattice dynamics of solids is offered. It is based on first-principles molecular dynamics simulations and provides a consistent way to extract the best possible harmonic - or higher…
The lattice dynamics in substitutional disordered alloys with constituents having large size differences is driven by strong disorder in masses, inter-atomic force constants and local environments. In this letter, a new first-principles…
Here we introduce a new approach to compute the finite temperature lattice dynamics from first-principles via the newly developed slave mode expansion. We study PbTe where inelastic neutron scattering (INS) reveals strong signatures of…
We review our recent development of a first-principles lattice dynamics method that can treat anharmonic effects nonperturbatively. The method is based on the self-consistent phonon theory and temperature-dependent phonon frequencies can be…
The crystal structure and local spontaneous polarization of (BaTiO3)m/(SrTiO3)n superlattices is calculated using a first-principles density functional theory method. The in-plane lattice constant is 1% larger than the SrTiO3 substrate to…
A comparative study between PbTiO$_3$, PbZrO$_3$, and the solid solution PbZr$_{0.5}$Ti$_{0.5}$O$_3$ is performed on the soft mode lattice dynamics within the first Brillouin Zone. We consider the six unique B-site orderings for…
We report first principles density functional studies using plane wave basis sets and pseudopotentials and all electron linear augmented plane wave (LAPW) of the relative stability of various ferroelectric and antiferroelectric supercells…
Vibration properties of Zn(1-x)Be(x)Se, a mixed II-VI semiconductor haracterized by a high contrast in elastic properties of its pure constituents, ZnSe and BeSe, are simulated by first-principles calculations of electronic structure,…
Conventional methods to calculate the thermodynamics of crystals evaluate the harmonic phonon spectra and therefore do not work in frequent and important situations where the crystal structure is unstable in the harmonic approximation, such…
The hybrid halide perovskite CH3NH3PbI3 exhibits a complex structural behaviour, with successive transitions between orthorhombic, tetragonal and cubic polymorphs at ca. 165 K and 327 K. Herein we report first-principles lattice dynamics…
Femtosecond optical pulses at mid-infrared frequencies have opened up the nonlinear control of lattice vibrations in solids. So far, all applications have relied on second order phonon nonlinearities, which are dominant at field strengths…
We report first principles calculations of the phonon dispersions of PbTe both for its observed structure and under compression. At the experimental lattice parameter we find a near instability of the optic branch at the zone center, in…
We report first principles linear response calculations on NaCoO$_2$. Phonon frequencies and eigenvectors are obtained throughout the Brillouin zone for two geometries with different Na site occupancies. While most of the phonon modes are…
Vibrational dynamics governs the fundamental properties of molecular crystals, shaping their thermodynamics, mechanics, spectroscopy, and transport phenomena. However desirable, the first-principles calculation of solid-state vibrations,…
By means of first-principles calculations, various properties of SrRuO3 are investigated, focusing on its lattice dynamical properties. Despite having a Goldschmidt tolerance factor very close to 1, the phonon dispersion curves of the…