Two-dimensional Hubbard model with nearest- and next-nearest-neighbor hopping

1987 ◽  
Vol 35 (7) ◽  
pp. 3359-3368 ◽  
Author(s):  
H. Q. Lin ◽  
J. E. Hirsch
Keyword(s):  
Hubbard Model ◽  
Nearest Neighbor ◽  
Two Dimensional

TWO-DIMENSIONAL QUARTER-FILLED EXTENDED HUBBARD MODEL AT STRONG COUPLING

2005 ◽  
Vol 19 (01n03) ◽  
pp. 213-216
Author(s):  
W. F. LEE ◽  
H. Q. LIN
Keyword(s):  
Hubbard Model ◽  
Correlation Functions ◽  
Nearest Neighbor ◽  
Spin Correlation ◽  
Perturbation Approach ◽  
Effective Hamiltonian ◽  
Two Dimensional ◽  
Extended Hubbard Model ◽  
Neighbor Interaction ◽  
Electron Hopping

In this paper, we generalized the perturbation approach to study the quasi-two-dimension extended Hubbard model. This model is characterizing by intra-chain electron hopping t, on-site Column interaction U, nearest-neighbor interaction V, and inter-chain electron hopping t′ and nearest-neighbor interaction V′. An effective Hamiltonian up to sixth-order in t/U, t/V, t/V′, t′/U, t′/V and t′/V′ expansion was obtained and the spin-spin correlation functions were calculated. We presented results for t=t′, V=V′.

Frustration Effects in the Two-Dimensional Hubbard Model

1999 ◽  
Vol 13 (29n31) ◽  
pp. 3552-3554
Author(s):  
HAI QING LIN ◽  
JUN LI
Keyword(s):  
Hubbard Model ◽  
Quantum Monte Carlo ◽  
Nearest Neighbor ◽  
Pair Correlation ◽  
Mean Field ◽  
Magnetic Phase Diagram ◽  
Two Dimensional ◽  
The Mean ◽  
Quantum Monte Carlo Simulations ◽  
Frustration Effects

We discuss frustration effects by studying the two-dimensional Hubbard model with nearest-neighbor(t) and next-nearest-neighbor(t′) hoppings. We present results obtained by the mean-field solution, the exact diagonalization technique, and the quantum Monte Carlo simulations. Questions to be addressed are: (1) magnetic phase diagram; (2) domain formation; and (3) superconducting pair correlation functions.

scholarly journals INHOMOGENEOUS d-WAVE SUPERCONDUCTIVITY AND ANTIFERROMAGNETISM IN A TWO-DIMENSIONAL EXTENDED HUBBARD MODEL WITH NEAREST-NEIGHBOR ATTRACTIVE INTERACTION

2007 ◽  
Vol 21 (10) ◽  
pp. 573-584 ◽  
Author(s):  
W. P. SU
Keyword(s):  
Phase Separation ◽  
Hubbard Model ◽  
Cuprate Superconductors ◽  
Nearest Neighbor ◽  
Minimum Energy ◽  
Mean Field Approximation ◽  
Attractive Interaction ◽  
Two Dimensional ◽  
Extended Hubbard Model ◽  
D Wave

To understand the interplay of d-wave superconductivity and antiferromagnetism, we consider a two-dimensional extended Hubbard model with nearest neighbor attractive interaction. The Hamiltonian is solved in the mean field approximation on a finite lattice. In the impurity-free case, the minimum energy solutions show phase separation as predicted previously based on free energy argument. The phase separation tendency implies that the system can be easily rendered inhomogeneous by a small external perturbation. Explicit solutions of a model including weak impurity potentials are indeed inhomogeneous in the spin-density-wave and d-wave pairing order parameters. Relevance of the results to the inhomogeneous cuprate superconductors is discussed.

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