Related papers: Soft Phonon Mode Dynamics in Aurivillius Type Stru…
We report our Raman studies of a new lead-free relaxor ferroelectrics, Ba0.85Ca0.15Ti0.9Zr0.1O3 (BCTZO). The Raman modes of BCTZO are compared with those of BaTi0.8Zr0.2O3 (BTZO), and BaTiO3 (BTO). Also, they are compared with the…
The continuous displacive phase transition in SrTiO$_3$ near $T_c \approx 105$ K features a central elastic peak in neutron scattering investigations at temperatures above $T_c$, i.e., before the corresponding soft phonon mode is overdamped…
Barium zirconate BaZrO3 is one of few perovskites that is claimed to retain an average cubic structure down to 0K at ambient pressure, while being energetically very close to a tetragonal phase obtained by condensation of a soft phonon mode…
We have carried out temperature-dependent inelastic neutron scattering measurements of YMnO3 over the temperature range 50 - 1303 K, covering both the antiferromagnetic to paramagnetic transition (70 K), as well as the ferroelectric to…
We report high-resolution inelastic x-ray measurements of the soft phonon mode in the charge-density-wave compound TiSe$_2$. We observe a complete softening of a transverse optic phonon at the L point, i.e. q = (0.5, 0, 0.5), at T ~…
The octahedral tilting and ferroelectric-like structural transition of LiOsO3 metallic perovskite [Nature Materials 12, 1024 (2013)] was examined using first-principles density-functional theory. In LiOsO3, a-a-a- octahedral titling mode is…
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 slow zero-sound mode expected near the Mott transition in strongly interacting two-dimensional Fermi systems that are neutral is shown to persist as the physical sound mode in the case that the fermion carries electronic charge and is…
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…
We measured the temperature dependent infrared reflectivity spectra of MnF2 between 4 K and room temperature. We show that the phonon spectrum undergoes a strong renormalization at TN. The ab-initio calculation we performed on this compound…
We propose a symmetry-based framework for constructing effective harmonic phonon models using a symmetry-adapted multipole basis. By decomposing the force-constant matrix into bond-centered electric multipoles, we identify the minimal…
Phonons, quantized vibrations of the atomic lattice, are fundamental to understanding thermal transport, structural stability, and phase behavior in crystalline solids. Despite advances in computational materials science, most predictions…
Local positional disorder in soft, anharmonic materials has emerged as a central factor in shaping their electronic, vibrational, optical, and transport properties. Viewed mainly as a source of performance degradation, recent theoretical…
EuAl$_4$ is a rare earth intermetallic in which competing itinerant and/or indirect exchange mechanisms give rise to a complex magnetic phase diagram, including a centrosymmetric skyrmion lattice. These phenomena arise not in the tetragonal…
The t-t'-t''-J model of electrons interacting with three phonon modes (breathing, apical breathing, and buckling) is considered. The wave-vector dependence of the matrix elements of the electron-phonon interaction leads to opposite…
The normal ferroelectric to paraelectric phase transition in model ferroelectric materials such as BaTiO3 is typically characterized by a sharp, well-defined dielectric constant peak at a specific transition temperature. However, under…
Spin-phonon interactions are central to many interesting phenomena, ranging from superconductivity to magnetoelectric effects. Yet, they are believed to have a negligible influence on the structural behavior of most materials. For example,…
Cuprates are promising candidates for study in developing higher temperature superconductors. A thorough understanding of a material's phonon modes enables further investigation of its emergent properties, however, no complete reference of…
The phase diagram of Sr_1-xEu_xTiO_3 is determined experimentally by electron paramagnetic resonance and resistivity measurements and analyzed theoretically within the self-consistent phonon approximation as a function of x ([0.03-1.0]).…
First-principles calculations are used in order to investigate phonon anomalies in non-magnetic and magnetic Heusler alloys. Phonon dispersions for several systems in their cubic L2$\mathrm{_1}$ structure were obtained along the [110]…