Role Of Electron-phonon Interaction Research Articles

Role of electron-phonon interaction on quasiparticle dispersion in the strongly correlated cuprate superconductors

The role of the electron-phonon (el-ph) interaction in high-${T}_{c}$ cuprates is investigated theoretically by considering correlated electrons interacting with Holstein phonons within the two-dimensional single-band Hubbard model in the limit of large Coulomb interaction. It is shown that the electron-phonon interaction gives rise to a kink in the dispersion along the nodal direction and to a peak/dip/hump structure in the one-electron spectral weight whose dependence on temperature, isotope substitution, and doping is discussed in relation to recent photoemission experiments on the nodal quasiparticles in Bi2201 and LSCO. A comparison with these experiments shows that electron correlations play a crucial role in the determination of the kink position, size, and doping dependence. We also show that the ``unusual'' oxygen isotope shift in the real part of the self-energy, experimentally observed in the optimally doped Bi2212 samples, can be qualitatively explained within the framework that incorporates both strong electron correlations and the adiabatic electron-phonon interaction.

On the role of electron-phononinteraction in the resistance anisotropy of two-dimensionalelectrons in GaAs heterostructures

The contribution of the electron-phonon interaction to the energyof a unidirectional charge-ordered state (stripe phase) oftwo-dimensional electrons in GaAs heterostructures is analysed. Thedependence of the energy on the direction of the electron-densitymodulation is calculated. It is shown that in electron layerssituated close to the (001) surface the interference between thepiezoelectric and the deformation potential interaction causes apreferential orientation of the stripes along the [110] axis.

Role of electron-phonon interaction in resonant x-ray Raman scattering by polymers and solids

We present a theory of radiative resonant x-ray Raman scattering by solids and polymers beyond the Born-Oppenheimer approximation. The role of electron-phonon coupling of the intermediate core ex ...

Infrared reflectivity spectroscopy of electron-phonon interactions

The crucial role of electron-phonon interactions and their signatures in optical conductivity deduced from the analysis of infrared-visible reflection spectra is reviewed. The usefulness of a general phenomenological model able to describe the couplings of phonons, polarons, plasmon, superconducting condensate, is discussed. Among other examples of applications, the problem of the signature of Cooper pair condensation in the superconducting phase of high-Tc cuprates is discussed in the framework of London and Mattis-Bardeen models.

Manifestation of electron-phonon interaction in phonon anomaly, superconductivity and transport properties of layered 2 H-NbS 2

Role of electron-phonon interaction in physical properties of 2 H-NbS 2 is elucidated microscopically. Characteristic mode and wave vector dependences of the electron-phonon interaction cause remarkable frequency renormalization of the Σ 1 phonon modes around q = ⅔ΓM, which consist mainly of the Nb vibrations. The superconducting and the transport spectral functions have significant values only in the low-frequency range ( ω < 20 meV) corresponding to the Nb vibrations. The superconducting transition temperature and the tunneling spectra are obtained by solving the Eliashberg equation. The electrical and thermal resistivities calculated by solving the Boltzmann equation with the use of the transport spectral function agree with observations.

Role of electron-phonon interaction in lattice dynamics and superconductivity of oxide spinel LiTi2O4

The lattice dynamics of an oxide spinel LiTi2O4 is studied by taking account of the electron-phonon (EP) interaction derived on the basis of the realistic tight-binding bands fitted to the first-principles bands. Due to the characteristic dependences of the EP interaction on wavevectors and vibrational modes, a remarkable frequency renormalization of the O vibrational modes, which hybridize with the Ti vibrational modes, is obtained over a wide region of the Brillouin zone. The overall features of the calculated phonon density of states are in agreement with those observed by the inelastic neutron scattering measurements. By using the EP interaction and the renormalized phonon frequencies we have calculated the EP spectral functionα2F(ω). The superconducting transition temperature, gap function, and tunneling spectra are calculated by solving the Eliashberg equation. The results agree well with the observations.

The role of electron-phonon interaction in oxide superconductors

The electron-phonon (EP) interaction and lattice dynamics are investigated microscopically for oxide superconductors, Ba x K 1− x BiO 3 (BKB) and La 2− x Sr x CuO 4 (LSC), on the basis of their realistic tight-bi nding bands fitted to the first-principle bands of each compound. By using the EP interaction and renormalized phonons we have calculated the spectral functions of BKB and LSC. In the framework of the phonon-mediated pairing mechanism, superconducting properties such as the transition temperature, the gap function and the tunneling spectra are calculated by solving the Eliashberg equation. The results for BKB are in good agreement with observations. For LSC, the calculated results are compared with recent observations and discussed in connection with those for BKB.

Electron-phonon interactions in energetic displacement cascades.

The role of electron-phonon interactions in energetic displacement cascades in metals is evaluated by considering the diffusion of electrons in a localized heat spike. It is found that the electronic system in this region always falls out of equilibrium with the lattice at long times and that whether electronic equilibrium is achieved at short times depends almost catastrophically on the parameters that describe the electron-phonon interaction. Neglect of the electron-phonon coupling may lead to overestimates of thermal spike temperatures in many metals.

DC transport in amorphous semiconductors

We report results for the transport properties of amorphous semiconductors in the absence of interactions. The role of electron-phonon interactions is also discussed.

Role of Electron-Phonon Interaction in the Theory of Infrared Divergence in Metals

correlation function are studied in the Born approximation. A new formulation is developed which relates the hole correlation function to the retarded polarization propagator of the electron gas. Previously obtained results for the free-electron gas at finite temperature are recovered. The Migdal approximation is employed to find an expression for the imaginary part of the polarization propagator and it is seen that although the strength of the singularity is potentially modified by a constant factor the time dependence is not changed. Inclusion of the electron-phonon interaction via the Migdal form for the electron spectral weight func­ tion has no effect on the hole correlation function if the one-electron density of states varies slowly on the scale of the width of the spectral weight function. Similarity of this behavior to that of the nuclear spin relaxation in electron-phonon system is pointed out.

The Role of Electron-Phonon Interaction in the Impurity Conduction of Semiconductors

The Role of Electron-Phonon Interaction in the Impurity Conduction of Semiconductors