Related papers: Phonon dispersion curves and thermodynamic propert…
We present a comparative Raman scattering study of metallic rutile oxides (RuO$_2$ and IrO$_2$) and insulating rutiles (TiO$_2$ and SnO$_2$). Temperature-dependent Raman spectra reveal that the metallic compounds exhibit pronounced phonon…
An increasing number of theoretical calculations on few-layer materials have been reporting a non-zero sound velocity for all three acoustic phonon modes. In contrast with these reports, here we show that the lowest phonon dispersion branch…
Recently colossal positive volume thermal expansion has been found in the framework compounds Ag3Co(CN)6 and Ag3Fe(CN)6. Phonon spectra have been measured using the inelastic neutron scattering technique as a function of temperature and…
Phonon drag may be harnessed for thermoelectric generators and devices. Here, we demonstrate the geometric control of the phonon-drag contribution to the thermopower. In nanometer-thin electrically conducting $\beta$-Ga$_2$O$_3$ films…
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…
This study investigates the ultrafast dynamics of coherent phonons and phonon-polaritons in lithium niobate (LiNbO$_{3}$) crystals using reflective pump-probe spectroscopy with 25-fs time resolution. In addition to several coherent optical…
We present a combined experimental and theoretical study of the surface vibrational modes of the topological insulator (TI) Bi$_2$Se$_3$ with particular emphasis on the low-energy region below 10 meV that has been difficult to resolve…
In this work, the Effective Phonon Dispersion of $\beta$- (Al$_x$Ga$_{1-x}$)$_2$O$_3$ alloy is investigated using the Phonon unfolding formalism. To capture the true randomness of the system, supercells are designed using the technique of…
We have calculated the dispersion curves of H vibrational modes on Pt(111), using first-principles, total energy calculations based on a mixed-basis set and norm-conserving pseudopotentials. Linear response theory and the harmonic…
Electron-phonon interaction is of central importance for the electrical and heat transport properties of metals, and is directly responsible for charge-density-waves or (conventional) superconducting instabilities. The direct observation of…
Applying the path integral formalism we study the equilibrium thermodynamics of the phonon field both in the Holstein and in the Su-Schrieffer-Heeger models. The anharmonic cumulant series, dependent on the peculiar source currents of the…
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…
Infrared reflectivity spectra of cubic SrMnO$_{3}$ ceramics reveal 18 % stiffening of the lowest-frequency phonon below the antiferromagnetic phase transition occurring at T$_{N}$ = 233 K. Such a large temperature change of the polar phonon…
The phonon and electronic properties, the Eliashberg function and the temperature dependence of resistance of electride Ca2N are investigated by the DFT-LDA plane-wave method. The phonon dispersion, the partial phonon density of states and…
We calculated the phonon dispersion relations of ZnX (X=Se, Te) employing ab initio techniques. These relations have been used to evaluate the temperature dependence of the respective specific heats of crystals with varied isotopic…
A condensate of pairs in an isolated, homogeneous, unpolarised, finite-size spin 1/2 Fermi gas at low nonzero temperature T, undergoes with time a phase change with a random component, due to coupling to the gas thermal phonons. With the…
The frequencies of transverse-optical $\Gamma$ phonons in KNbO$_3$ and KTaO$_3$ are calculated in the frozen-phonon scheme making use of the full-potential linearized muffin-tin orbital method. The calculated frequencies in the cubic phase…
Transverse acoustic (TA) phonon waves are analogous to electromagnetic waves and can carry a certain angular momentum. In this paper, we study the electron-TA phonon couplings in three-dimensional pentatellurides and explore the conditions…
We analyze the ground states and the elementary collective excitations (phonons) of a class of systems, which form cluster crystals in the absence of attractions. Whereas the regime of moderate-to-high-temperatures in the phase diagram has…
We present the vibrational properties and phonon dispersion for quasi-2D hybrid organic-inorganic perovskites (BA)$_2$CsPb$_2$I$_7$, (HA)$_2$CsPb$_2$I$_7$, (BA)$_2$(MA)Pb$_2$I$_7$, and (HA)$_2$(MA)Pb$_2$I$_7$ calculated from first…