Variational cluster approximation study of the one-dimensional Holstein-Hubbard model at half filling

2011 ◽  
Vol 83 (3) ◽  
Author(s):  
Alexandre Payeur ◽  
David Sénéchal
Keyword(s):  
Hubbard Model ◽  
Cluster Approximation ◽  
One Dimensional ◽  
Half Filling ◽  
The One ◽  
Variational Cluster Approximation

scholarly journals Exact Ground-State Properties and Phase Transitions within One-dimensional Hubbard Model in Magnetic Field

2000 ◽  
Vol 14 (29n31) ◽  
pp. 3771-3776
Author(s):  
C. Yang ◽  
A. N. Kocharian ◽  
Y. L. Chiang
Keyword(s):  
Magnetic Field ◽  
Hubbard Model ◽  
Ground State ◽  
Chemical Potential ◽  
Interaction Strength ◽  
Upper And Lower Bounds ◽  
One Dimensional ◽  
Ground State Properties ◽  
Half Filling ◽  
The One

The phase diagram, the Bethe-ansatz ground-state properties, including the chemical potential μ, the spin (magnetic) and charge susceptibilities, are calculated within the one-dimensional Hubbard model in entire range of interaction strength (-∞< U/t<+∞), magnetic field (h≥ 0) and all electron concentrations (0≤n≤1). The continuous and smooth variation of μ with n and h in the vicinity of n=1 points on the gapless character of charge excitations at U<0 and provides rigorous upper and lower bounds for μ. The spin (magnetic) susceptability χ at half-filling changes discontinuously as U→0 and is strongly enhanced by electron repulsion, comparing with that of the non-interactig case. The compressibility κ ch increases with n at U<0 and shows non-monotonous behavior with a dramatic increase at U>0. Variations of κ ch -1 in both repulsive and attractive cases qualitatively well reproduces corresponding behavior of charge stiffness.

METAL-INSULATOR TRANSITION IN THE HUBBARD MODEL

1996 ◽  
Vol 10 (18) ◽  
pp. 863-871
Author(s):  
ARIANNA MONTORSI ◽  
MARIO RASETTI
Keyword(s):  
Hubbard Model ◽  
Ground State ◽  
Insulator Transition ◽  
Full Model ◽  
Dimensional Model ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
One Dimensional ◽  
Half Filling ◽  
The One

We study the metal-insulator transition of the d-dimensional Hubbard model by treating the hopping term between adjacent 1-d chains in the frame of a Clifford linearization scheme, and keeping the full model along the chains. A general equation for the critical point is worked out in terms of the correlation functions of the one-dimensional model, assuming that the transition is of the second order. The equation, which holds at any temperature, is here investigated especially at T=0, where the latter condition holds true. The solution shows the existence of an insulating ground state in any d only at half-filling for U strictly positive, as in the exact 1-d case. The transition is found to be related to a parameter reminiscent of entropy.

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