Related papers: Antiadiabatic Phonons and Superconductivity in Eli…
By using variational wave functions and quantum Monte Carlo techniques, we investigate the interplay between electron-electron and electron-phonon interactions in the two-dimensional Hubbard-Holstein model. Here, the ground-state phase…
We study the isotope effects arising from the coupling of correlated electrons with dispersionless phonons by considering the Hubbard-Holstein model at half-filling within the dynamical mean-field theory. In particular we calculate the…
We investigate in the framework of linear response theory the complete phonon dispersion, phonon induced electronic charge response, electron-phonon interaction and dielectric and infrared properties of the high-temperature superconductors…
We provide a mathematical description, based on d-wave Eliashberg theory, of the strong correlation between the experimentally observed softening of Raman modes associated with in-plane oxygen motions and the corresponding superconducting…
Temperature dependent Raman scattering studies in polycrystalline MgB2(10<T<300 K)reveal that the E2g phonon does not experience any self energy renormalization effect across the superconducting critical temperature Tc ~ 40 K. In contrast,…
Specific heat and resistivity measurements were performed on polycrystalline samples of the solid-solution Y_xLu_(1-x)Ni2B2C in order to determine thermodynamic properties such as the specific-heat difference, the thermodynamic critical…
Recent work on an electron-phonon model in two-dimensions is reviewed and some new results are presented. We utilize both Quantum Monte Carlo simulations and Migdal-Eliashberg theory. The type of electron-ion coupling considered is on-site.…
Emergence of superconductivity in a two-band system coupled with breathing and Jahn-Teller phonons is discussed in a weak-coupling limit. With the use of a standard quantum mechanical procedure, the phonon-mediated attraction is derived.…
Superconductors without inversion symmetry in their crystal structure are known to exhibit unconventional properties. Recently, based on the measured temperature dependence of the magnetic field penetration depth, superconductivity in…
We investigate the antiadiabatic limit of an antiferromagnetic S=1/2 Heisenberg chain coupled to Einstein phonons via a bond coupling. The flow equation method is used to decouple the spin and the phonon part of the Hamiltonian. In the…
There is rich experimental evidence that granular superconductors and superconducting films often exhibit a higher transition temperature, $T_{c}$, than that in bulk samples of the same material. This paper suggests that this enhancement…
The phenomenology of LiFeAs superconductor can be explained in the framework of a four-band s$\pm$-wave Eliashberg theory. We have examined the experimental data available in literature and we have found out that it is possible to reproduce…
Superconducting properties of hypothetical simple hexagonal CaB2 are studied using the fully anisotropic Eliashberg formalism based on electronic and phononic structures and electron-phonon interactions which are obtained from ab initio…
We reconsider the long-standing problem of the effect of spin fluctuations on the critical temperature and isotope effect in a phonon-mediated superconductor. Although the general physics of the interplay between phonons and paramagnons had…
Electron-phonon superconductors at high pressures have displayed the highest values of critical superconducting temperature $T_c$ on record, now rapidly approaching room temperature. Despite the importance of high-$P$ superconductivity in…
We uncover that the competition between electron-electron correlations and electron-phonon interactions gives rise to unexpectedly huge enhancement of the superconducting transition temperature, several hundreds percent larger ($\geq$ 200…
The effect of Holstein electron-phonon interaction on a Hubbard model close to a Mott-Hubbard transition at half-filling is investigated by means of Dynamical Mean-Field Theory. We observe a reduction of the effective mass that we interpret…
We analyze superonductivity in MgB$_2$ observed below $T_c=39$ K resulting from electron-phonon coupling involving a mode at $\hbar \omega_1 = 24$ meV and most importantly the in-plane B-B $E_{2g}$ vibration at $\hbar \omega_2=67$ meV. The…
We present a first principles investigation of the lattice dynamics and electron-phonon coupling of the superconductor MgB_2 and the isostructural AlB_2 within the framework of density functional perturbation theory using a mixed-basis…
We present a comparative analysis of the validity of Eliashberg theory for the cases of fermions interacting with an Einstein phonon and with soft nematic fluctuations near an Ising-nematic/Ising-ferromagnetic quantum-critical point (QCP).…