相关论文: Born effective charges and vibrational spectra in …
Large values of Born effective charges are generally considered as reliable indicators of the genuine tendency of an insulator towards ferroelectric instability. However, these quantities can be very much influenced by strong electron…
Strong electron-electron interactions are known to significantly modify the electron-phonon coupling relative to the predictions of density functional theory, but this effect is challenging to calculate with realistic theories of strongly…
Calculations of the zone center optical mode frequencies (including LO-TO splitting), Born effective charges Z$^*_{\alpha\alpha}$ for each atom, dielectric constants $\epsilon_{0}$ and $\epsilon_{\infty}$, and the dielectric response in the…
The theory of Raman scattering by the electron--phonon coupled system in metals and heavily doped semiconductors is developed taking into account the Coulomb screening and the electron--phonon deformation interaction. The Boltzmann equation…
Recent optical studies in c-axis oriented superconducting MgB$_2$ films indicate that the electron-phonon coupling is weak [tu01]. We reinforce this conclusion by examining the raw reflectance data; its frequency dependence is incompatible…
We report the first systematic measurements of the Raman scattering by electrons in elemental metals of Al, Mo, Nb, Os, Pb, Re, Ta, Ti, V, W and metallic compound La$B_6$. Experimental spectra are modelled on the base of the band…
The theory of electron-phonon interaction in the presence of strong correlation has been investigated in the present work. Due to the so called spin-charge separation, it is argued that the electron-phonon interaction in the strongly…
Since the discovery of superconductivity in the alkali-doped fullerenes \cite{hebard}, the electron-phonon interaction has been the primary suspect for superconductivity in this class of compounds. In this paper we first provide a…
The mechanisms for strong electron-phonon coupling predicted for hydrogen-rich alloys with high superconducting critical temperature ($T_c$) are examined within the Migdal-Eliashberg theory. Analysis of the functional derivative of $T_c$…
Spectral distribution functions of electron-phonon interaction $\alpha^2F(\omega )$ obtained by ab initio linear--response calculations are used to describe various superconducting and transport properties in a number of elemental metals…
We investigate the interplay between the electron-electron and the electron-phonon interaction in the Hubbard-Holstein model. We implement the flow-equation method to investigate within this model the effect of correlation on the…
To investigate the possibility whether electron-phonon coupling can enhance orbital fluctuations in iron-based superconductors, we develop an ab initio method to construct the effective low-energy models including the phonon-related terms.…
Advances in light sources and time resolved spectroscopy have made it possible to excite specific atomic vibrations in solids and to observe the resulting changes in electronic properties but the mechanism by which phonon excitation causes…
Coupling between electrons and phonons (lattice vibrations) drives the formation of the electron pairs responsible for conventional superconductivity. The lack of direct evidence for electron-phonon coupling in the electron dynamics of the…
In conventional superconductors, the most direct evidence of the mechanism responsible for superconductivity comes from tunneling experiments in which a clear image of the electron-phonon interaction is revealed. The observed structure in…
We develop an ab initio method to simulate the infrared vibrational response of metallic systems in the framework of time-dependent density functional perturbation theory. By introducing a generalized frequency-dependent Born effective…
The effect of electron-phonon interactions in the conductance through metallic atomic wires is theoretically analyzed. The proposed model allows to consider an atomic size region electrically and mechanically coupled to bulk electrodes. We…
Metals exhibit nonequilibrium electron and lattice subsystems at transient times following femtosecond laser excitation. In the past four decades, various optical spectroscopy and time-resolved diffraction methods have been used to study…
In insulators, Born effective charges describe the electrical polarization induced by the displacement of individual atomic sublattices. Such a physical property is at first sight irrelevant for metals and doped semiconductors, where the…
Observed optical reflectivity in the infrared spectral region is compared with theoretical predictions in a strongly coupled electron-phonon system. Starting from a Froehlich Hamiltonian, the spectral functions and their temperature…