Phase transitions in the Haldane-Hubbard model within coherent potential approximation

2018 ◽  
Vol 532 ◽  
pp. 139-143 ◽  
Author(s):  
Duc-Anh Le ◽  
Minh-Tien Tran ◽  
Thi-Thanh-Mai Tran ◽  
Thi-Thao Nguyen ◽  
Thi-Huong Nguyen ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Hubbard Model ◽  
Coherent Potential Approximation ◽  
Potential Approximation

MOTT TRANSITION IN THE HALF-FILLED HUBBARD MODEL ON THE HONEYCOMB LATTICE WITHIN COHERENT POTENTIAL APPROXIMATION

2013 ◽  
Vol 27 (07) ◽  
pp. 1350046 ◽  
Author(s):  
DUC ANH LE
Keyword(s):  
Hubbard Model ◽  
Quantum Monte Carlo ◽  
Mean Field Theory ◽  
Mean Field ◽  
Coulomb Repulsion ◽  
Mott Transition ◽  
Coherent Potential Approximation ◽  
Honeycomb Lattice ◽  
Potential Approximation ◽  
Good Agreement

Using the coherent potential approximation, we study zero-temperature Mott transition in the half-filled Hubbard model on the honeycomb lattice. Although a pseudogap is already present for the non-interacting case, the gap will not occur until the onsite Coulomb repulsion exceeds a critical value U ≈ 3.6t, where t is the hopping integral. When increasing U/t, the density of states at the Fermi energy first goes up gradually from zero and after reaching a maximum it goes down to zero again. Our calculated critical interaction UC/t is in very good agreement with the ones obtained by quantum Monte Carlo simulation and cluster dynamical mean-field theory.

REENTRANT CHARGE ORDERING BEHAVIOUR IN THE EXTENDED HUBBARD MODEL

2001 ◽  
Vol 15 (26) ◽  
pp. 1217-1224 ◽  
Author(s):  
ANH TUAN HOANG
Keyword(s):  
Hubbard Model ◽  
Three Dimensional ◽  
Charge Ordering ◽  
Coherent Potential Approximation ◽  
Coulomb Energy ◽  
Extended Hubbard Model ◽  
Potential Approximation ◽  
Ordering Transition

We study the charge ordering behavior in a three-dimensional extended Hubbard model using the Coherent potential approximation (CPA). It is shown that the charge ordering transition occurs due to the competition between kinetic and Coulomb energy. At various band fillings a simple reentrant behavior of the charge ordering transition is found.

scholarly journals Charge Ordering under a Magnetic Field in the Extended Hubbard Model

2003 ◽  
Vol 17 (20n21) ◽  
pp. 1103-1110
Author(s):  
Duc Anh Le ◽  
Anh Tuan Hoang ◽  
Toan Thang Nguyen
Keyword(s):  
Magnetic Field ◽  
Critical Temperature ◽  
Hubbard Model ◽  
Charge Ordering ◽  
Coherent Potential Approximation ◽  
Extended Hubbard Model ◽  
Potential Approximation ◽  
Relative Variation ◽  
Band Filling ◽  
The One

We study the charge ordering behavior under magnetic field H in the extended Hubbard model within the coherent potential approximation. At quarter filling, for small H we find that the relative variation of critical temperature is quadratic with the coefficient α smaller than the one for conventional spin-Peierls systems. For intermediate fields, a melting of the charge ordering on decreasing temperature under fixed H at various band filling is found.

THE SELF CONSISTENT COHERENT POTENTIAL APPROXIMATION TO THE HUBBARD MODEL

1990 ◽  
Vol 04 (08) ◽  
pp. 549-560 ◽  
Author(s):  
MASSIMO CORRIAS
Keyword(s):  
Hubbard Model ◽  
Interaction Strength ◽  
Exact Formula ◽  
Coherent Potential Approximation ◽  
The Self ◽  
Potential Approximation ◽  
Double Occupancy ◽  
Occupancy Probability ◽  
Self Consistent

We introduce, by an exact formula for the double occupancy probability δ in the Hubbard model, a self consistent version of the CPA which is aimed at taking into better account correlations of the electrons motion. We show that CPA breaks down at large values of the interaction strength, and we suggest a way of overcoming this limitation along the lines of the model proposed here.

The Equivalence of CPA and Hubbard-III-I Approximation in the Two-Band Hubbard Model

1997 ◽  
Vol 11 (18) ◽  
pp. 779-784
Author(s):  
Hoang Anh Tuan
Keyword(s):  
Hubbard Model ◽  
Anderson Model ◽  
Equation Of Motion ◽  
Coherent Potential Approximation ◽  
The Self ◽  
Periodic Anderson Model ◽  
Potential Approximation ◽  
Scattering Correction

We study a two-band Hubbard model using the Coherent Potential Approximation (CPA) and equation of motion decoupling scheme with scattering correction (Hubbard-III-I approximation). We show that above two approximations are completely equivalent to each other for the Periodic Anderson Model (PAM) as well as for the Self-doped Mott System (SMS).

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