Related papers: Slave-boson Formalism for Superconducting Pairing …
Motivated by recent experimental study of antiferromagnetic property of honeycomb compound In$_{3}$Cu$_{2}$VO$_{9}$ [Yan \textit{et al.}, PRB \textbf{85}, 085102 (2012)], we explore possible superconductivity and its coexistence with…
We argue that the combination of strong repulsive interactions and high magnetic fields can generate electron pairing and superconductivity. Inspired by the large lattice constants of moir\'e materials, which make large flux per unit cell…
We derive the shape of the high-energy features due to a weakly coupled boson in cuprate superconductors, as seen experimentally in Bi_2 Sr_2 Ca_1 Cu_2 O_8+x (BSCCO) by Lee et al. [Nature (London) 442, 546 (2006)]. A simplified model is…
We study a strongly interacting quantum dot connected to a normal and to a superconducting lead. By means of the slave-boson technique we investigate the low temperature regime and discuss electrical transport through the dot. We find that…
Understanding the microscopic mechanism of coexisting long-range orders (such as lattice supersolidity) in strongly correlated systems is a subject of immense interest. We study the possible manifestations of long-range orders, including…
Motivated by superconductivity (SC) in layered nitrides, we study an ionic-Hubbard model on a honeycomb lattice, which consists of two sublattices with an energy-level offset, by using an optimization variational Monte Carlo method.…
We present a strong-coupling expansion of the Bose-Hubbard model which describes both the superfluid and the Mott phases of ultracold bosonic atoms in an optical lattice. By performing two successive Hubbard-Stratonovich transformations of…
We study a one-dimensional system of strongly correlated bosons on a dynamical lattice. To this end, we extend the standard Bose-Hubbard Hamiltonian to include extra degrees of freedom on the bonds of the lattice. We show that this minimal…
One promising way to enhance superconductivity is to have coexisting wide and incipient narrow bands, where the Fermi level intersecting the wide band lies just above the narrow band, by which finite-energy spin fluctuations act as glue to…
We solve the orbitally degenerate two-band Hubbard model within dynamical mean field theory and map out the instabilities to various symmetry-broken phases based on an analysis of the corresponding lattice susceptibilities. Phase diagrams…
We investigate pairing symmetry and transition temperature in the trellis-lattice Hubbard model. We solve the \'Eliashberg equation using the third-order perturbation theory with respect to the on-site repulsion $U$. We find that a…
We study conductance spectroscopy of a two-dimensional junction between a normal metal and a strongly-correlated superconductor in an applied magnetic field in the Pauli limit. Depending on the field strength the superconductor is either in…
In this work we use functional integral techniques to examine the nearest neighbour attractive Hubbard model on a quasi-2D lattice. It is a simple phenomenological model for the high-Tc cuprates that allows both extended (non-local) s- and…
We present an analysis of a system of weakly coupled Hubbard chains based on combining an exact study of spectral functions of the uncoupled chain system with a renormalization group method for the coupled chains. For low values of the…
As a weak-coupling analogue of hole-doped $S=1$ Haldane systems, we study two models for coupled chains via Hund coupling; coupled Hubbard chains, and a Hubbard chain coupled with an $S=1/2$ Heisenberg chain. The fixed point properties of…
Using a slave boson representation of multi-band Hubbard models, we investigate a two-band model relevant to layered perovskites in the vicinity of half-filling. Beside the strong influence of the Hund's rule coupling, we obtain that the…
The charge dynamical response function of the Hubbard model is investigated on the square lattice in the thermodynamical limit. The obtained charge excitation spectra consist of a continuum, a gapless collective mode with anisotropic…
A superconductor emerges as a condensate of electron pairs, which bind despite their strong Coulomb repulsion. Eliashberg's theory elucidates the mechanisms enabling them to overcome this repulsion and predicts the transition temperature…
The possibility of superconductivity in doped and undoped triangular antiferromagnets is discussed. Using the Bethe-Salpeter (B-S) equation, it is shown that the exchange of RPA paramagnons on a triangular lattice Hubbard model leads to…
Full or empty narrow bands near the Fermi level are known to enhance superconductivity by promoting scattering processes and spin fluctuations. Here, we demonstrate that doublon-holon fluctuations in systems with half-filled narrow bands…