Related papers: Superconducting mechanism for the cuprate Ba$_2$Cu…
We investigate the superconductivity in Sr$_2$RuO$_4$ on the basis of the three-dimensional three-band Hubbard model. We propose a model with Coulomb interactions among the electrons on the nearest-neighbor Ru sites. In our model the…
We investigate superconductivity that may exist in the doped BaCoSO, a multi-orbital Mott insulator with a strong antiferromagnetic ground state. The superconductivity is studied in both t-J type and Hubbard type multi-orbital models by…
The enigmatic mechanism underlying unconventional high-temperature superconductivity, especially the role of lattice dynamics, has remained a subject of debate. Theoretical insights have long been hindered due to the lack of an accurate…
Comparison is made of the electronic structure of the little-studied layered transition metal oxide LiNbO$_2$ with that of Na$_x$CoO$_2$, which has attracted tremendous interest since superconductivity was discovered in its hydrate.…
We perform first principles band calculation of the newly discovered superconductor LaO$_{1-x}$F$_x$BiS$_2$, and study the lattice structure and the fluorine doping dependence of the gap between the valence and conduction bands. We find…
Starting with a minimal model for the CuO$_2$ planes with the on-site Hilbert space reduced to a charge triplet of the three effective valence centers [CuO$_4$]$^{7-,6-,5-}$ (nominally Cu$^{1+,2+,3+}$) with different conventional spin,…
The single-site dynamical mean-field approximation is used to solve a model of high-Tc cuprate superconductors which includes both d_{x^2-y^2} and d_{3z^2-r^2} orbitals on the Cu as well as the relevant oxygen states. Both T (with apical…
Multilayered cuprates possess not only the highest superconducting temperature transition but also offer a unique platform to study disorder-free CuO$_2$ planes and the interplay between competing orders with superconductivity. Here, we…
We theoretically investigate the unconventional superconductivity in the newly discovered infinite-layer nickelates Nd$_{1-x}$Sr$_{x}$NiO$_{2}$ based on a two-band model. By analyzing the transport experiments, we propose that the doped…
High-Tc superconductivity with possible $T_{c}\approx 80K$ has been reported in the single crystal of $\text{La}_{3}\text{Ni}_{2}\text{O}_{7}$ under high pressure. Based on the electronic structure given from the density functional theory…
High $T_c$ cuprate superconductors are characterized by two robust features: their strong electronic correlations and their intrinsic dynamical local lattice instabilities. Focusing on exclusively that latter, we picture their parent state…
Inspired by a recently proposed superconducting mechanism for a new cuprate superconductor Ba$_2$CuO$_{3+\delta}$, we theoretically design an unconventional nickelate superconductor with $d^8$ electron configuration. Our strategy is to…
We investigate superconductivity in a two-orbital Hubbard model on a square lattice by applying fluctuation exchange approximation. In the present model, the symmetry of the two orbitals are assumed to be that of an s orbital. Then, we find…
Motivated by the recent discovery of superconductivity in La$_3$Ni$_2$O$_7$ under pressure, we discuss the basic ingredients of a model that captures its microscopic physics under pressure tuning. We anchor our description in terms of the…
Motivated by the bilayer cuprate superconductors and nickelate superconductor La$_3$Ni$_2$O$_7$, we investigate the evolution from intralayer to interlayer superconductivity based on a bilayer two-leg $t$-$J$-$J_{\bot}$ model, where $t$ is…
At the beginning of cuprate superconductors, the interlayer tunneling (ILT) and Lawrence-Doniach (L-D) models, which connect the CuO planes by Josephson coupling were considered the leading theoretical proposals for these materials.…
We study the mean-field phase diagram of the two-dimensional (2D) Hubbard model in the Lieb lattice allowing for spin and charge density waves. Previous studies of this diagram have shown that the mean-field magnetization surprisingly…
We study the pairing and superconducting properties of the attractive Hubbard model in two quasi one-dimensional topological lattices: the Creutz and sawtooth lattices. They share two peculiar properties: each of their band structures…
Although the mechanism of superconductivity in the cuprates remains elusive, it is generally agreed that at the heart of the problem is the physics of doped Mott insulators. The cuprate parent compound has one unpaired electron per Cu site,…
The quest to understand the nature of superconductivity in cuprates has spotlighted the pair density wave (PDW) -- a superconducting state characterized by a spatially modulated order parameter. Despite significant advances in understanding…