Related papers: Pseudo-gap and vertex correction of electron-phono…
The unclear relationship between cuprate superconductivity and the pseudogap state remains an impediment to understanding the high transition temperature (Tc) superconducting mechanism. Here we employ magnetic-field-dependent scanning…
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 $T_c$…
The underdoped cuprate superconductors are characterized by the opening of the pseudogap, while such an aspect of the pseudogap effect should be reflected in the low-energy electronic structure (LEES). Here the effect of the pseudogap on…
We study pseudogap behavior in a metal near an antiferromagnetic instability and apply the results to electron-doped cuprates. We associate pseudogap behavior with thermal magnetic fluctuations and compute the fermionic self-energy along…
The mechanism of spin-phonon coupling in high-T$_C$ copper oxides is explored from band calculations on La$_{(2-x)}$Sr$_x$CuO$_4$ and HgBa$_2$CuO$_4$ systems. The LMTO band calculations, based on the local density approximation, are made…
Superconductivity occurs in electrochemically doped molybdenum dichalcogenides samples thicker than four layers. While the critical temperature (Tc) strongly depends on the field effect geometry (single or double gate) and on the sample…
We investigate strong-coupling properties of a two-dimensional ultracold Fermi gas in the normal phase. In the three-dimensional case, it has been shown that the so-called pseudogap phenomena can be well described by a (non-self-consistent)…
Mathematical correct method for extraction of the complex superconducting energy gap parameter and electron- phonon interaction function from the tunnel density of states is presented. The computer program is shown to be robust against…
Close to optimal doping, the copper oxide superconductors show 'strange metal' behavior, suggestive of strong fluctuations associated with a quantum critical point. Such a critical point requires a line of classical phase transitions…
We calculate the isotope coefficients $\alpha$ and $\alpha^\ast$ for the superconducting critical temperature $T_c$ and the pseudogap temperature $T^\ast$ in a mean-field treatment of the t-J model including phonons. The pseudogap phase is…
We investigate the pseudogap onset temperature $T^*$, the superconducting transition temperature $T_c$ and the general nature of the pseudogap phase using a diagrammatic BCS-Bose Einstein crossover theory. This decoupling scheme is based on…
We describe the approach of the superconducting state as a sequence of cross-over phenomena. As the temperature is decreased, uncorrelated pairing of the electrons leads to the opening of a pseudogap at T_F^*. Upon further lowering the…
A pairing gap and coherence are the two hallmarks of superconductivity. In a classical BCS superconductor they are established simultaneously at Tc. In the cuprates, however, an energy gap (pseudogap) extends above Tc. The origin of this…
The generic band structure of high-T$_C$ copper oxides is simulated by the nearly free-electron model (NFE) in two dimensions (2-D) with parameters from band calculations. Interaction between phonons and spin waves will cause potential…
We use a symmetry-constrained variational procedure to construct a generalization of BCS to include Cooper pairs with non-zero momentum and angular momentum. The resulting gap equations are solved at zero and finite temperature, and the…
Based on recently proposed anti-ferromagnetic spin fluctuation exchange models for $d_{x^2-y^2}$-superconductors, we show that coupling to harmonic phonons {\it{cannot}} account for the observed isotope effect in the cuprate high-$T_c$…
Strong electron-phonon interactions in cuprates and other high-temperature superconductors have gathered support over the last decade in a large number of experiments. Here I briefly introduce the Froehlich-Coulomb multi-polaron model of…
We show that, at weak to intermediate coupling, antiferromagnetic fluctuations enhance d-wave pairing correlations until, as one moves closer to half-filling, the antiferromagnetically-induced pseudogap begins to suppress the tendency to…
We calculate Tc map in region of weak electron-phonon coupling based on simple phonon spectrum. By using linear-response method and density functional theory, we calculate phonon spectra and Eliashberg functions of simple metals under…
The SU(2)xU(1) Chern-Simons spin-charge gauge approach developed earlier to describe the transport properties of the cuprate superconductors in the ``pseudogap'' regime, in particular, the metal-insulator crossover of the in-plane…