相关论文: Optimal Hubbard models for materials with nonlocal…
We investigate the Peierls-Feynman-Bogoliubov variational principle to map Hubbard models with nonlocal interactions to effective models with only local interactions. We study the renormalization of the local interaction induced by…
The physics of non-local exchange interactions in graphene sheets is studied within a $\pi$-orbital tight-binding model using a Hartree-Fock approximation and Coulomb interactions modified at short distances by lattice effects and at large…
We use the Gutzwiller method to investigate the importance of the on-site Coulomb interaction in graphene. We apply it to Hubbard Hamiltonian to study the renormalization of the kinetic energy in graphene due to the on-site Coulomb…
To obtain an effective many-body model of graphene and related materials from first principles we calculate the partially screened frequency dependent Coulomb interaction. In graphene, the effective on-site (Hubbard) interaction is U_00 =…
We propose a systematic procedure for constructing effective models of strongly correlated materials. The parameters, in particular the on-site screened Coulomb interaction U, are calculated from first principles, using the GW…
The determination of the effective Coulomb interactions to be used in low-energy Hamiltonians for materials with strong electronic correlations remains one of the bottlenecks for parameter-free electronic structure calculations. We propose…
The effect of the long-range Coulomb interaction on the realization of the Kohn-Luttinger superconductivity in idealized monolayer doped graphene is studied. It is shown that the allowance for the Kohn-Luttinger renormalizations up to the…
We propose a nonlocal theory of single-particle excitations. It is based on an off-diagonal effective medium and the projection operator method for treating the retarded Green function. The theory determines the nonlocal effective medium…
Recent experiments on twisted bilayer graphene show the urgent need for establishing a low-energy lattice model for the system. We use the constrained random phase approximation to study the interaction parameters of such models taking into…
The effective on-site Coulomb interaction (Hubbard $U$) between localized \textit{d} electrons in 3\textit{d}, 4\textit{d}, and 5\textit{d} transition metals is calculated employing a new parameter-free realization of the constrained…
The Coulomb interaction is widely known to enhance the effective mass of interacting particles and therefore tends to favor a localized state at commensurate filling. Here, we will show that, in contrast to this consensus, in a van der…
The low-energy theory of interacting electrons on graphene's two-dimensional honeycomb lattice is derived and discussed. In particular, the Hubbard model in the large-N limit is shown to have a semi-metal - antiferromagnetic insulator…
The effective on-site Coulomb interaction (Hubbard $U$) between 5$f$ electrons in actinide metals (Th-Cf) is calculated with the framework of density-functional theory (DFT) using linear response approach. The $U$ values seldom rely on the…
We give an update of the situation concerning the effect of electron-electron interactions on the physics of a neutral graphene system at low energies. We revise old renormalization group results and the use of 1/N expansion to address…
We study the influence of ferromagnetic nonlocal exchange on correlated electrons in terms of a $SU(2)$-Hubbard-Heisenberg model and address the interplay of on-site interaction induced local moment formation and the competition of…
In this work, we address the question of calculating the local effective Coulomb interaction matrix in materials with strong electronic Coulomb interactions from first principles. To this purpose, we implement the constrained random phase…
The layered graphene systems exhibit the rich and unique excitation spectra arising from the electron-electron Coulomb interactions. The generalized tight-binding model is developed to cover the planar/buckled/cylindrical structures,…
Recently synthesized 3D materials with Dirac spectrum exhibit peculiar electric transport qualitatively different from its 2D analogue, graphene. Neglecting impuritiy scattering, the real part of the conductivity is strongly frequency…
The effective on-site Coulomb interaction (Hubbard $U$) between localized electrons at crystal surfaces is expected to be enhanced due to the reduced coordination number and reduced subsequent screening. By means of first principles…
It has been proposed that interactions lead to ferromagnetism on a zigzag edge of a graphene sheet. While not yet directly studied experimentally, dramatically improving techniques for making and studying clean zigzag edges may soon make…