Related papers: Anomalous transverse optic phonons in SnTe and PbT…
Although extensive experimental and theoretical works have been conducted to understand the ballistic and diffusive phonon transport in nanomaterials recently, direct observation of temperature and thermal nonequilibrium of different phonon…
Measurements of the proton's form factor ratio made with polarization transfer show a striking discrepancy relative to the ratio extracted from unpolarized elastic electron-proton scattering cross sections. One hypothesis is that the…
We present temperature dependent inelastic neutron scattering measurments, accompanied byab-initio calculations of phonon spectra and elastic properties as a function of pressure to understand anharmonicity of phonons and to study the…
Two-dimensional (2D) metallic systems with intrinsically low lattice thermal conductivity are rare, yet they are of great interest for next-generation energy and electronic technologies. Here, we present a comprehensive first-principles…
The intrinsic linewidth $\Gamma_{TA}$ of the transverse acoustic (TA) phonon observed in the relaxor ferroelectric compound Pb(Mg$_{1/3}$Nb$_{2/3})_{0.8}$Ti$_{0.2}$O$_3$ (PMN-20%PT) begins to broaden with decreasing temperature around 650…
Due to the long range interaction in lead telluride (PbTe), the transverse optical (TO) phonon becomes soft around the Brillouin zone center. Previous studies have postulated that this zone-center softening causes the low thermal…
Inelastic and elastic neutron scattering have been used to study a single crystal of the Ni$_{54}$Mn$_{23}$Al$_{23}$ Heusler alloy over a broad temperature range. The paper reports the first experimental determination of the low-lying…
We report inelastic neutron scattering measurements of the phonon density-of-states in superconducting Sr0.6K0.4Fe2As2 (Tc=30 K) and Ca0.6Na0.4Fe2As2 (Tc=18 K). Compared with the parent compound BaFe2As2 doping affects mainly the lower and…
In this work, we investigate the softening of the in-plane transverse acoustic phonon driven by electronic nematicity in BaFe$_2$(As$_{1-x}$P$_x$)$_2$ using inelastic X-ray scattering, with a focus on the optimally doped sample ($x = 0.31$)…
We report inelastic light scattering experiments on CaFe_2As_2 in the temperature range of 4 to 290 K. In in-plane polarizations two Raman-active phonon modes are observed at 189 and 211 cm-1, displaying A_1g and B_1g symmetries,…
A crack free and high structural quality Sr2Nb2O7 single crystals were grown by the optical float zone method using optimized growth parameters. Laue pattern confirms single crystalline nature of the grown crystal. Temperature dependent…
Anomalous thermal expansion behaviour of several open frame-work compounds has been extensively investigated using the techniques of inelastic neutron scattering and lattice dynamics. These compounds involve increasing level of structural…
We have used neutron scattering techniques to characterize the diffuse scattering and lattice dynamics in single crystals of the relaxor PMN from 10K to 900K. We observed two distinct types of diffuse scattering. The first is weak,…
Here we report on an elastic and inelastic neutron scattering study addressing the effect of electric fields on quantum paraelectric SrTiO3. Our elastic scattering results find small changes as a function of field in a superlattice…
We report inelastic light scattering studies on Ca(Fe0.97Co0.03)2As2 in a wide spectral range of 120-5200 cm-1 from 5K to 300K, covering the tetragonal to orthorhombic structural transition as well as magnetic transition at Tsm ~ 160K. The…
Parent compounds of Fe-based superconductors undergo a structural phase transition from a tetragonal to an orthorhombic structure. We investigated the temperature dependence of the frequencies of transverse acoustic (TA) phonons that…
The possibility of magnetic-order induced phonon anisotropy in single crystals of MnO and NiO is investigated using inelastic neutron scattering. Below Tn both compounds exhibit a splitting in their transverse optical phonon spectra of…
We present a detailed ab-initio study of semi-classical transport in n-ZnSe using Rode's iterative method. Inclusion of ionized impurity, piezoelectric, acoustic deformation and polar optical phonon scattering and their relative importance…
Inelastic neutron-scattering experiments have been carried out on polycrystalline samples of the FeSe$_{1-x}$ superconductors. We report the phonon density of states for FeSe$_{1-x}$ with Tc$\approx$8 K. The phonon cutoff frequency is…
We present a study of the lattice dynamical properties of superconducting SrPt$_3$P ($T_c = 8.4$ K) via high-resolution inelastic x-ray scattering (IXS) and ab initio calculations. Density functional perturbation theory including spin-orbit…