Related papers: Superconductivity close to the charge-density-wave…
We study s-wave superconductivity in the two-dimensional square lattice attractive Hubbard Hamiltonian for various inhomogeneous patterns of interacting sites. Using the Bogoliubov-de Gennes (BdG) mean field approximation, we obtain the…
The recently discovered vanadium-based kagome metals AV$_3$Sb$_5$ (A = K, Rb, Cs) offer the possibility to study the interplay between competing electronic orderings, such as charge density order and superconductivity. We focus on the…
The strength and effect of Coulomb correlations in the (superconducting when hydrated) x~1/3 and ``enhanced'' x~2/3 regimes of Na(x)CoO2 are evaluated using the correlated band theory LDA+U method. Our results, neglecting quantum…
In this thesis, I study a two-dimensional extended Hubbard model in the weak coupling limit. Quite generally, the electron gas is unstable towards a superconducting state even in the absence of phonons. However in the special case of a…
We propose a theory for quasi-two-dimensional transition metal dichalcogenides that provides a unified microscopic picture of the charge density wave (CDW) and superconducting phases. We show, based on the electron-phonon coupling and Fermi…
The electron-phonon (e-ph) interaction remains of great interest in condensed matter physics and plays a vital role in realizing superconductors, charge-density-waves (CDW), and polarons. We study the two-dimensional Holstein model for e-ph…
The interplay between different quantum phases plays an important role in strongly correlated systems, such as high-$T_c$ cuprates, quantum spin systems, and ultracold atoms. In particular, the application of effective field theory model…
We investigate the interplay between charge order and superconductivity near an antiferromagnetic quantum critical point using sign-problem-free Quantum Monte Carlo simulations. We establish that, when the electronic dispersion is…
The issue of whether $d$-wave superconductivity (SC) occurs in the square-lattice Hubbard model with $U$ of order of the bandwidth has been one of the most debated issues to emerge from the study of high temperature SC. Here, we report…
We have studied the d-wave pairing-instability in the two-dimensional Holstein-Hubbard model at the level of a full fluctuation exchange approximation which treats both Coulomb and electron-phonon (EP) interaction diagrammatically on an…
The electron-positive fermion gas in three dimensions and $T=0$ is modeled as two independent fermion gases interacting via the coulomb interaction. The main advantage of the simple model is that all existing results from the electron gas…
We report two surprising results regarding the nature of the spatial broken symmetries in the two-dimensional (2D), quarter-filled band with strong electron-electron interactions. First, in direct contradiction to the predictions of…
We calculate the density of states of a layered superconductor in which there are two layers per unit cell. One of the layers contains a d-wave pairing interaction while the other is a normal metal. The goal of this article is to understand…
The possibility of realizing pair density wave (PDW) phases, in which Cooper pairs have a finite momentum, presents an interesting challenge that has been studied in a wide variety of systems. In conventional superconductors, this is only…
We study electron-electron Coulomb interactions in electronic systems whose Fermi surfaces possess a finite electric dipole density. Although there is no net dipole moment, we show that electric monopole-dipole interactions can become…
We consider a simple model of a quasi-one-dimensional conductor in which two order parameters (OP) may coexist, i.e., the superconducting OP $\Delta$ and the OP $W$ that characterizes the amplitude of a charge-density wave (CDW). In the…
Electron-lattice coupling effects in low dimensional materials give rise to charge density wave (CDW) order and phase transitions. These phenomena are critical ingredients for superconductivity and predominantly occur in metallic model…
Recently, superconductivity was discovered at very low densities in slightly misaligned graphene multilayers. Surprisingly, despite extremely low electronic density (about $10^{-4}$ electrons per unit cell), these systems realize…
We consider Kohn-Luttinger mechanism for superconductivity in a two-dimensional electron gas confined to a narrow well between two metallic planes with two occupied subbands with Fermi momenta $k_{FL} > k_{FS}$. On the basis of a…
Superconductivity is one of the most intriguing properties of matter described by an attractive interaction that bounds electrons into Cooper pairs. To date, the highest critical temperature at ambient conditions is achieved in copper…