Related papers: Relation of Extended Van Hove Singularities to Hig…
Ever since BCS theory was first formulated it was recognized that a large electronic density of states at the Fermi level was beneficial to enhancing $T_c$. The A15 compounds and the high temperature cuprate materials both have had an…
There is a great deal of interest in attributing the high critical temperatures of the cuprates to either the proximity of the Fermi level to a van Hove singularity or to structure of the superconducting pairing potential in momentum space…
It is shown that the square-root Van Hove singularity in the density of states (DOS), associated with extended saddle-point features in the electronic spectra of cuprates, leads to a nonmonotonic dependence of Tc on the position of the…
A flattened electronic band is one of several possible routes for increasing the strength of the pairing interactions in a superconductor. With this in mind, we show here that thermodynamic measurements of the high-Tc cuprates reveal an…
We show that an interacting electronic system with a single ordinary or extended Van Hove point, which crosses the Fermi energy, is unstable against triplet superconductivity. The pairing mechanism is unconventional. There is no Cooper…
We observe that H$_3$S has a bcc structure and, with nearest neighbour hopping only, a strong singularity occurs at zero energy. This singularity is accompanied with a highly nested Fermi surface, which is {\it not} conducive to a stable…
We discuss the evolution of high-order Van Hove singularities (hoVHSs) that carry faster-than logarithmic divergences over a wide range of parameters in cuprate-like electronic band dispersions. Numerical analysis gives insight into the…
The Van Hove singularity (VHS) provides a paradigm for the study of the role of peaks in the density of states (dos) on electronic properties. More importantly, it appears to play a major role in the physics of the high-T_c superconductors,…
We report an angle-resolved photoemission spectroscopy (ARPES) study of KFe$_2$As$_2$ and CsFe$_2$As$_2$, revealing the existence of a van Hove singularity affecting the electronic properties. As a result of chemical pressure, we find a…
Van Hove singularities (vHs) located close to the Fermi level in Kagome superconductors AV3Sb5 (A = K, Rb, Cs) have profound influence on their electronic and transport characteristics. Specifically, magneto-transport and susceptibility…
The superconducting transition temperature $T_c$ of the two-dimensional attractive Hubbard model is computed in the vicinity of both ordinary (logarithmic) and higher-order (power-law) Van Hove singularities using determinant quantum Monte…
We apply the Coherent Potential Approximation (CPA) to a simple extended Hubbard model with a nearest and next nearest neighbour hopping for disordered superconductors with s-, d- and p-wave pairing. We show how the Van Hove singularities…
In the family of the iron-based superconductors, the $RE$FeAsO-type compounds (with $RE$ being a rare-earth metal) exhibit the highest bulk superconducting transition temperatures ($T_{\mathrm{c}}$) up to $55\ \textrm{K}$ and thus hold the…
One of interesting open questions for the high transition temperature (Tc) superconductivity in sulfur hydrides is why high pressure phases of H3S have extremely high Tc's. Recently, it has been pointed out that the presence of the van Hove…
In two dimensions the non-interacting density of states displays a Van Hove singularity (VHS) which introduces an intrinsic electron-hole asymmetry, absent in three dimensions. We show that due to this VHS the strong-coupling analysis of…
We examine the generic phase behavior of high-Tc cuprate superconductors in terms a universal van Hove singularity in the strongly overdoped region. Using a rigid ARPES-derived dispersion we solve the BCS gap equation and show that the…
We describe here a minimal theory of tight binding electrons moving on the square planar Cu lattice of the hole-doped cuprates and mixed quantum mechanically with pairs of them (Cooper pairs). Superconductivity occurring at the transition…
The three band structure of the extended Emery model for the copper-oxide layered materials is analyzed for all the values of the effective tight-binding parameters. The model is characterized by the Cu-O site energy splitting, the Cu-O…
In this paper we study the effects of the strong coupling superconductivity on the normal state electronic structure. We point out that the pseudogap phenomena in High-T_c cuprates are naturally explained as a precursor of the strong…
We have performed density functional calculations in conjunction with the linearized Migdal-Eliashberg equations and the functional derivative approach, which takes into account the energy-range dependence of the density of states at the…