scholarly journals Antiferromagnetism in the Hubbard model on the honeycomb lattice: A two-particle self-consistent study

2015 ◽  
Vol 92 (4) ◽  
Author(s):  
S. Arya ◽  
P. V. Sriluckshmy ◽  
S. R. Hassan ◽  
A.-M. S. Tremblay
Keyword(s):  
Hubbard Model ◽  
Honeycomb Lattice ◽  
Self Consistent

scholarly journals Kane-Mele-Hubbard model on theπ-flux honeycomb lattice

2014 ◽  
Vol 90 (7) ◽  
Author(s):  
Martin Bercx ◽  
Martin Hohenadler ◽  
Fakher F. Assaad
Keyword(s):  
Hubbard Model ◽  
Honeycomb Lattice

scholarly journals Self-Consistent Calculation of Particle-Hole Diagrams on the Matsubara Frequency: Flex Approximation

1997 ◽  
Vol 08 (05) ◽  
pp. 1145-1158
Author(s):  
J. J. Rodríguez-Núñez ◽  
S. Schafroth
Keyword(s):  
Hubbard Model ◽  
Imaginary Part ◽  
Chemical Potential ◽  
Order Approximation ◽  
The Self ◽  
Green Functions ◽  
Matsubara Frequency ◽  
Self Energy ◽  
Peak Structure ◽  
Self Consistent

We implement the numerical method of summing Green function diagrams on the Matsubara frequency axis for the fluctuation exchange (FLEX) approximation. Our method has previously been applied to the attractive Hubbard model for low density. Here we apply our numerical algorithm to the Hubbard model close to half filling (ρ =0.40), and for T/t = 0.03, in order to study the dynamics of one- and two-particle Green functions. For the values of the chosen parameters we see the formation of three branches which we associate with the two-peak structure in the imaginary part of the self-energy. From the imaginary part of the self-energy we conclude that our system is a Fermi liquid (for the temperature investigated here), since Im Σ( k , ω) ≈ w2 around the chemical potential. We have compared our fully self-consistent FLEX solutions with a lower order approximation where the internal Green functions are approximated by free Green functions. These two approches, i.e., the fully self-consistent and the non-self-consistent ones give different results for the parameters considered here. However, they have similar global results for small densities.

scholarly journals Effective spin couplings in the Mott insulator of the honeycomb lattice Hubbard model

2012 ◽  
Vol 14 (11) ◽  
pp. 115027 ◽  
Author(s):  
Hong-Yu Yang ◽  
A Fabricio Albuquerque ◽  
Sylvain Capponi ◽  
Andreas M Läuchli ◽  
Kai Phillip Schmidt
Keyword(s):  
Hubbard Model ◽  
Mott Insulator ◽  
Honeycomb Lattice ◽  
Effective Spin

scholarly journals Effects of correlations on honeycomb lattice in ionic-Hubbard model

2015 ◽  
Vol 379 (14-15) ◽  
pp. 1053-1056 ◽  
Author(s):  
M. Ebrahimkhas ◽  
Z. Drezhegrighash ◽  
E. Soltani
Keyword(s):  
Hubbard Model ◽  
Honeycomb Lattice ◽  
Ionic Hubbard Model

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.

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