Using the observed temperature dependence of a-Si:H photon absorption spectrum and the weak-phonon interaction second-order transition theory, phonon-coupling enhanced photon absorption is predicted for a-Si-Ge and a-Si-Sn alloys. The ab initio calculated electron and phonon properties of the alloyed amorphous phase show minimally altered electronic states and significant redshifted phonon ener...

The contributions to the dynamic form factor S(Q, U) arising from interference between its one-phonon and multiphonon parts have been observed in the scattering of neutrons from potassium. Interference makes two qualitatively distinct contributions to S(Q, U). One is approximately proportional to the one-phonon part, S,(Q, U), and as a result contributes scattering intensity largely within the ...

Phonon optics concerns operations with high-frequency acoustic waves in solid media in a similar way to how traditional optics operates with the light beams (i.e. photons). Phonon optics experiments with coherent terahertz and sub-terahertz phonons promise a revolution in various technical applications related to high-frequency acoustics, imaging, and heat transport. Previously, phonon optics u...

By using first principles density functional perturbation theory, we computed the phonon dispersions of 4 nm diameter 5,0 carbon nanotubes. We investigated the development of phonon anomalies as the Fermi surface sharpens. The soft modes are related to the nesting features in the electronic band structure. We found that two phonon branches are strongly renormalized by electron-phonon coupling, ...

Fluorescence and phosphorescence phonon sidebands of isotopic mixed hexamethylbenzene crystals at 2°K are presented. The external phonons can be observed separately from the semi-internal (methyl torsion) ones. The nature of the electronic or vibronic state has observable but not drastic effects on the exciton-phonon coupling function. Likewise, the exciton delocalization is of minor importance...

Femtosecond laser pulses are used to excite coherent optical phonons in single crystal Bi2Te3 thin films. Oscillations from lowand high-frequency A1g phonon modes are observed. A perturbation model based on molecular dynamics reveals various possibilities of phonon generation due to complex interactions among different phonon modes. In order to elucidate the process of phonon generation, measur...

In this paper we investigate the spin-current and its shot-noise spectrum in a single-molecule quantum dot coupled with a local phonon mode. We pay special attention on the effect of phonon on the quantum transport property. The spin-polarization dependent current is generated by a rotating magnetic filed applied in the quantum dot. Our results show the remarkable influence of phonon mode on th...

Ab initio molecular dynamics, supported by inelastic neutron scattering and nuclear resonant inelastic x-ray scattering, showed an anomalous thermal softening of the M_{5}^{-} phonon mode in B2-ordered FeTi that could not be explained by phonon-phonon interactions or electron-phonon interactions calculated at low temperatures. A computational investigation showed that the Fermi surface undergoe...

We study squeezed quantum states of phonons, which allow the possibility of modulating the quantum fluctuations of atomic displacements below the zero-point quantum noise level of coherent phonon states. We calculate the corresponding expectation values and fluctuations of both the atomic displacement and lattice amplitude operators, and also investigate the possibility of generating squeezed p...