physica status solidi (b)

An information theoretical method (ITM) applied to the metal–insulator transition of the neutral hubbard model

E. Heiner

Published Jan 1, 1979• 4 citations

Abstract

Abstract By a minimization procedure of the information measure for the single particle spectral weight function (SWF) of fermions a method is found for the approximate calculation of the SWF. Using this method it is possible to overcome the shortcoming of the rigid shape ansatz for the SWF within the moment expansion method. The new method is applied to the neutral Hubbard model and a criterion for the localization of the quasi‐particles is given.

DOI: 10.1002/pssb.2220910108

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physica status solidi (b)

An information theoretical method (ITM) applied to the metal–insulator transition of the neutral hubbard model

E. Heiner

Published Jan 1, 1979• 4 citations

Publisher

Abstract

DOI: 10.1002/pssb.2220910108

Related papers

Roth's method and moment conservation of the spectral weight function for the neutral Hubbard model

E. Heiner

Abstract The method of Roth for the calculation of a (2 × 2 ) Green's function matrix is equivalent to the moment technique for the spectral weight function up to the fourth order. The method can be extended in order to derive a set of orthogonalized operators. With this method a selfconsistent calculation of the single‐particle Green's function and all important correlation functions of nearest neighbour sites is possible for the neutral Hubbard model. The results agree for a sc lattice in the strong correlation region at arbitrary temperatures with those of Shiba and Pincus for finite Hubbard systems. An antiferromagnetic coupling of neighboured lattice sites is increasing with a decrease of the temperature, a metalinsulator transition does not exist in this two‐pole approximation.Abstract The method of Roth for the calculation of a (2 × 2 ) Green's function matrix is equivalent to the moment technique for the spectral weight function up to the fourth order. The method can be extended in order to derive a set of orthogonalized operators. With this method a selfconsistent calculation of the single‐particle Green's function and all important correlation functions of nearest neighbour sites is possible for the neutral Hubbard model. The results agree for a sc lattice in the strong correlation region at arbitrary temperatures with those of Shiba and Pincus for finite Hubbard systems. An antiferromagnetic coupling of neighboured lattice sites is increasing with a decrease of the temperature, a metalinsulator transition does not exist in this two‐pole approximation.

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Single-particle spectral function of a generalized Hubbard model: Metal-insulator transition

Eduardo R. Gagliano, Armando A. Aligia, Liliana Arrachea +1 more

A generalized Hubbard model with correlated hoppings is studied at half filling using exact diagonalization methods. For certain values of the hopping parameters our results for several static properties, the Drude weight and the single-particle spectra function, suggest the occurrence of a metal-insulator transition (MIT) at a finite value of the local Coulomb interaction ${\mathit{U}}_{\mathit{c}}$ . We identify the regions of the hopping parameters where the MIT is of the Mott type. In these regions, for large U ${\mathit{U}}_{\mathit{c}}$ , we find a ferromagnetic ground state.A generalized Hubbard model with correlated hoppings is studied at half filling using exact diagonalization methods. For certain values of the hopping parameters our results for several static properties, the Drude weight and the single-particle spectra function, suggest the occurrence of a metal-insulator transition (MIT) at a finite value of the local Coulomb interaction ${\mathit{U}}_{\mathit{c}}$. We identify the regions of the hopping parameters where the MIT is of the Mott type. In these regions, for large U${\mathit{U}}_{\mathit{c}}$, we find a ferromagnetic ground state.

Physical review. B, Condensed matterMay 15, 199526 citations

U_{c}

, of the coupling constant (Hubbard

U

). The SWF at the Fermi points

k_{F}

\pmπ/2

jumps, as

U

increases, from a two-peak structure, the gap edges, to a four-peak structure accompanied by a (non-vanishing) minimum of the charge-gap. The two inner peaks of this structure show very small dispersion (flat bands) away from the Fermi points, whereas the outer peaks mark the edges of the Hubbard bands. No other signatures of abrupt change are detected in the SWF. The two regimes are physically realized in the angle-resolved photoelectron spectra of

(TaSe_{4})_{2}I

, and the blue-bronze

K_{0.3}MoO_{3}

, respectively.

{\mathit{U}}_{\mathit{c}}

. We identify the regions of the hopping parameters where the MIT is of the Mott type. In these regions, for large U

{\mathit{U}}_{\mathit{c}}

, we find a ferromagnetic ground state.