Coherent potential approximation

We apply the coherent potential approximation to study the three-component FalicovKimball model, in which single-component and two-component fermionic particles are mixed in an optical lattice. In the model, the heavy single-component fermionic particles are localized while the light two-component fermionic particles can hop in the lattice.

10p vispiderman 15-06-2023 6 2   Download

Using coherent potential approximation we study zero-temperature Mott transition of the half-filled Hubbard model in a two-dimensional square lattice with geometrical frustration. It turns out that the geometrical frustration reduces the gap between the Hubbard bands. As a result the metallic phase is stabilized up to a fairly large value of the on-site Coulomb interaction. We found that the critical value UC for the Mott transition is enhanced by the geometrical frustration. Our results are in good agreement with the ones obtained by the single-site dynamical mean-field theory.

7p thuyliebe 12-10-2018 31 1   Download

We calculate the temperature dependent conductivity in the half-filled ionic Hubbard model with an on-site Coulomb repulsion U and an ionic energy ∆ by mean of the coherent potential approximation. It is shown that for intermediate and large ∆ the largest conductivity occurs near the special value U = 2∆ at all temperatures T , for a fixed ∆ the region of finite conductivity [Uc1,Uc2] expands and its maximum decreases with increasing T . Our results are in good agreement with those derived from the determinant quantum Monte Carlo simulation.

5p thuyliebe 09-10-2018 17 1   Download

The electronic properties of strongly correlated systems with binary type of disorder are investigated using the coherent potential approximation. For half-filled system, two transitions from a band insulator via a metallic state to a Mott insulator are found with increasing the correlation strength of only one of the constituents. Our phase diagram is consistent with those obtained by the dynamical mean field theory.

6p thuyliebe 08-10-2018 32 1   Download