in this paper, for the first time we have studied theoretically the effect of exchange-correlation holes around electrons in gaalas/gaas/gaalas nanostructure on the temperature-dependent dynamic dielectric function of two-dimensional electron gas by employing random phase, stls and hubbard approximations. also, we have investigated another interesting system which is coupled quantum wells struc...

A new two-pole approximation in the Hubbard model. Two-pole approaches in the Hubbard model [1] and the Hubbard bands conception (being the consequence of a two-pole approximation) have been useful for understanding of the peculiarities of electric and magnetic properties of narrow-band materials [1]-[13]. However within the framework of two-pole approaches there are series of issues, in partic...

We calculate the one-particle density of states for the Mott–Hubbard insulating phase of the Hubbard model on a Bethe lattice in the limit of infinite coordination number. We employ the Kato–Takahashi perturbation theory around the strong-coupling limit to derive the Green function. We show that the Green function for the lower Hubbard band can be expressed in terms of polynomials in the bare h...

In this paper, we use the local density approximation+Hubbard U method to calculate the structural and electronic properties of low-spin LaCoO3. The Hubbard U is obtained by first principles and consistent with each fully optimized atomic structure at different pressures. With structurally consistent U, the fully optimized atomic structure agrees with experimental data better than the calculati...

We calculate the one-particle density of states for the Mott–Hubbard insulating phase of the Hubbard model on a Bethe lattice in the limit of infinite coordination number. We employ the Kato–Takahashi perturbation theory around the strong-coupling limit to derive the Green function. We show that the Green function for the lower Hubbard band can be expressed in terms of polynomials in the bare h...

Most of the double-counting formulas were historically derived by approximating the Hubbard interaction term (defined with the help of matrix elements Eq. 33) by some static approximation, either in the atomic limit, or, in Hartree-Fock limit. Such static approximations were argued to be a good substitute for the LDA treatment of the Hubbard interaction. Hence, the problem arrose, because it is...