The temperature dependence below Tc of the lineshape of optical phonons of different symmetry as seen in Raman scattering is investigated for superconductors with anisotropic energy gaps. It is shown that the symmetry of the electron-phonon vertex produces non-trivial couplings to an anisotropic energy gap which leads to unique changes in the phonon lineshape for phonons of different symmetry. ...

Pseudogaps due to sound modes: from incommensurate charge density waves to semiconducting wires. Abstract We consider pseudogap effects for electrons interacting with gapless modes. We study both generic 1D semiconductors with acoustic phonons and incom-mensurate charge density waves. We calculate the subgap absorption as it can be observed by means of the photo electron or tunneling spectrosco...

Inelastic light scattering in crystals has historically been treated as a spatially incoherent process, giving rise to incoherent optical radiation. Here we demonstrate that Raman scattering can be spatially coherent, in which case it depends on the dimensionality and symmetry of the scatterer. Using near-field spectroscopy, we measure a correlation length of ∼30  nm for the optical phonons in ...

The temperature dependence of the mobility in suspended graphene samples is investigated. In clean samples, flexural phonons become the leading scattering mechanism at temperature T≳10 K, and the resistivity increases quadratically with T. Flexural phonons limit the intrinsic mobility down to a few m(2)/V s at room T. Their effect can be eliminated by applying strain or placing graphene on a su...

We calculate the electron–phonon interaction coefficients for surface acoustic waves and for phonons in free standing quantum wells. These are used to derive the inelastic current through a double quantum dot caused by spontaneous emission of phonons. For the case of the free standing structure (phonon cavity), we predict a staircase–like inelastic current superimposed by van Hove singularities...

The dynamics of vortices in a superfluid film at the absolute zero of temperature is studied. The quantum-mechanical, i.e., “first-quantized” description is compared to a recently proposed quantum-field-theoretic, i.e., “second-quantized” description. The theory, consisting of the nonrelativistic effective action of phonons linearly coupled to a Chern-Simons term, is used to calculate the one-l...

Using first-order perturbation theory and deformation potential approximation, the interaction of electrons and holes with acoustic and optical phonons is investigated in silicon nanowires SiNWs with different diameters and crystallographic axis orientations. The electronic band structures for 110 and 100 SiNWs are obtained from a sp3d5s tight-binding scheme, while a continuum model is assumed ...

We report direct imaging of nanoscale thermal transport in single and few-layer graphene with approximately 50 nm lateral resolution using high vacuum scanning thermal microscopy. We observed increased heat transport in suspended graphene where heat is conducted by ballistic phonons, compared to adjacent areas of supported graphene, and observed decreasing thermal conductance of supported graph...

A recently developed long-wavelength continuum phenomenological model is employed to study the phonon tunneling through semiconductor heterostructures where the barrier parameters are varied gradually according to a Gaussian function. The optical modes of a Si/SixGe1Kx Gaussian superlattice are considered. Such structures allow the incident phonons to be nearly totally transmitted when the inci...

We measured the phonon density of states (DOS) of nanocrystalline Fe by resonant inelastic nuclear g-ray scattering. The nanophase material shows large distortions in its phonon DOS. We attribute the high energy distortion to lifetime broadening. A damped harmonic oscillator model for the phonons provides a low quality factor, Qu, averaging about 5, but the longitudinal modes may have been broa...