scholarly journals First-order metal-insulator transitions in the extended Hubbard model due to self-consistent screening of the effective interaction

2018 ◽  
Vol 97 (16) ◽  
Author(s):  
M. Schüler ◽  
E. G. C. P. van Loon ◽  
M. I. Katsnelson ◽  
T. O. Wehling
Keyword(s):  
Hubbard Model ◽  
Effective Interaction ◽  
Extended Hubbard Model ◽  
Metal Insulator ◽  
First Order ◽  
Self Consistent

scholarly journals Thermodynamics of the metal-insulator transition in the extended Hubbard model

2019 ◽  
Vol 6 (6) ◽  
Author(s):  
Malte Schüler ◽  
Erik van Loon ◽  
Mikhail Katsnelson ◽  
Tim Wehling
Keyword(s):  
Hubbard Model ◽  
Fermi Liquid ◽  
Insulator Transition ◽  
Extended Hubbard Model ◽  
Metal Insulator Transition ◽  
Local Interactions ◽  
Metal Insulator ◽  
First Order ◽  
Local Correlations ◽  
Non Local

In contrast to the Hubbard model, the extended Hubbard model, which additionally accounts for non-local interactions, lacks systemic studies of thermodynamic properties especially across the metal-insulator transition. Using a variational principle, we perform such a systematic study and describe how non-local interactions screen local correlations differently in the Fermi-liquid and in the insulator. The thermodynamics reveal that non-local interactions are at least in parts responsible for first-order metal-insulator transitions in real materials.

scholarly journals Doping-driven metal-insulator transitions and charge orderings in the extended Hubbard model

2017 ◽  
Vol 95 (12) ◽  
Author(s):  
K. J. Kapcia ◽  
S. Robaszkiewicz ◽  
M. Capone ◽  
A. Amaricci
Keyword(s):  
Hubbard Model ◽  
Extended Hubbard Model ◽  
Metal Insulator ◽  
Charge Orderings

scholarly journals SUPERCONDUCTING ORDER PARAMETERS IN THE EXTENDED HUBBARD MODEL: A SIMPLE MEAN-FIELD STUDY

2007 ◽  
Vol 21 (13n14) ◽  
pp. 2371-2383 ◽  
Author(s):  
J. S. THAKUR ◽  
M. P. DAS
Keyword(s):  
Hubbard Model ◽  
Nearest Neighbor ◽  
Mean Field ◽  
Order Parameters ◽  
Square Lattice ◽  
Extended Hubbard Model ◽  
Self Consistent ◽  
Frame Work ◽  
Field Formalism ◽  
Superconducting Pairing

The extended Hubbard model with nearest neighbor hopping and intersite interaction for a 2D square lattice has been studied within the frame work of a simple mean-field formalism. The self-consistent solutions of superconducting order parameters have been obtained for various fillings. The results indicate that superconducting pairing occurs on doping for the repulsive on-site U and attractive nearest neighbor V.

HIGH-DENSITY EXPANSION FOR THE EXTENDED HUBBARD MODEL

1987 ◽  
Vol 01 (05n06) ◽  
pp. 1277-1310 ◽  
Author(s):  
M. BARTKOWIAK
Keyword(s):  
Hubbard Model ◽  
Ground State ◽  
High Density ◽  
Extended Hubbard Model ◽  
Zeroth Order ◽  
Cluster Expansions ◽  
First Order ◽  
Expansion Technique ◽  
Density Expansion ◽  
Band Case

The Green’s-function diagrammatic high-density expansion technique for Hubbard’s operators is constructed and applied to the extended Hubbard model. The electron Green’s functions and the band structure of the ground state for arbitrary electron density are calculated in the zeroth-order in 1/z. The phase diagram, staggered magnetic susceptibility and the Néel temperature for the half-filled band case are derived in the first order of the high-density expansion. Connections of the high-density and linked cluster expansions are also discussed.

FIRST ORDER METAL-INSULATOR TRANSITION IN AN ALLOY ANALOGY APPROACH TO THE HUBBARD MODEL

1991 ◽  
Vol 05 (06n07) ◽  
pp. 1015-1032 ◽  
Author(s):  
MASSIMO CORRIAS
Keyword(s):  
Insulator Transition ◽  
Metal Insulator Transition ◽  
Potential Approximation ◽  
Metal Insulator ◽  
Hubbard Hamiltonian ◽  
First Order ◽  
Occupancy Probability ◽  
Potential Strength ◽  
Self Consistent ◽  
Dependent Factor

The self-consistent coherent potential approximation introduced in Ref. 3 is extended to the hopping part of the Hubbard Hamiltonian in an alloy analogy scheme. There results the renormalization of the unperturbed bandwidth w by the appearance of a spin and potential strength dependent factor Φσ(u), the latter leads — in the magnetically disordered case, at electron densities n not far from 1, for small values of the temperature k B T with respect to w and values of u smaller than those needed to cause the Hubbard splitting — to a first order metal-insulator transition: Φ and the double occupancy probability D undergo a sudden drop. It is also shown that in the approximation proposed the system becomes strongly ferromagnetic in the thermodynamic limit at n = 1 and T = 0 if u is sufficiently large.

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