Domain walls, spiral states, and phase separation in the extended Hubbard model: A Hartree-Fock analysis

1994 ◽  
Vol 50 (24) ◽  
pp. 17901-17909 ◽  
Author(s):  
Fengming Hu ◽  
Sanjoy K. Sarker ◽  
C. Jayaprakash
Keyword(s):  
Phase Separation ◽  
Hubbard Model ◽  
Domain Walls ◽  
Extended Hubbard Model ◽  
Hartree Fock

PHASE SEPARATION IN THE TWO-DIMENSIONAL HUBBARD MODEL

2005 ◽  
Vol 19 (01n03) ◽  
pp. 299-302 ◽  
Author(s):  
M. YU ◽  
H. Q. LIN
Keyword(s):  
Phase Separation ◽  
Hubbard Model ◽  
Coulomb Interaction ◽  
Single Band ◽  
Study Phase ◽  
Two Dimensional ◽  
Stripe Phase ◽  
Hartree Fock ◽  
Band Filling

In this paper, we study phase separation in the two-dimensional single-band Hubbard model with the unrestricted Hartree-Fock(UHF) method and the restricted Hartree-Fock (RHF) method. We perform the calculation for square lattices and rectangle lattices. It is observed that the stripe phase exists and it depends on three aspects: geometry of the lattice, Coulomb interaction U and band filling n. To gain more physical insights, we consider the Hubbard model with spin dependent hoppings: t↑ and t↓, and study the effect of varying [Formula: see text] on the phase separation.

On the possibility of phase separation in the extended Hubbard model

1990 ◽  
Vol 76 (12) ◽  
pp. 1333-1336 ◽  
Author(s):  
H. Fehske ◽  
V. Waas ◽  
H. Röder ◽  
H. Büttner
Keyword(s):  
Phase Separation ◽  
Hubbard Model ◽  
Extended Hubbard Model

Ground state of the half-filled extended Hubbard model beyond the Hartree-Fock approximation

1984 ◽  
Vol 102 (7) ◽  
pp. 323-326 ◽  
Author(s):  
A.M. Oleś ◽  
R. Micnas ◽  
S. Robaszkiewicz ◽  
K.A. Chao
Keyword(s):  
Hubbard Model ◽  
Ground State ◽  
Extended Hubbard Model ◽  
Hartree Fock

Phase separation in the 1-D extended Hubbard model

1997 ◽  
Vol 282-287 ◽  
pp. 1875-1876 ◽  
Author(s):  
H.Q. Lin ◽  
E. Gagliano ◽  
D.K. Campbell
Keyword(s):  
Phase Separation ◽  
Hubbard Model ◽  
Extended Hubbard Model

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.

Spin and Charge Density Waves in the Extended Hubbard Model: A Slave Boson Approach

1997 ◽  
Vol 11 (17) ◽  
pp. 2057-2074 ◽  
Author(s):  
S. Caprara ◽  
M. Avignon ◽  
D. D. Sarma
Keyword(s):  
Hubbard Model ◽  
Charge Density ◽  
Density Wave ◽  
Spin Density Wave ◽  
Nearest Neighbors ◽  
Charge Density Waves ◽  
Extended Hubbard Model ◽  
Hartree Fock ◽  
Charge Density Wave Phase ◽  
Half Filling

We use the extended Hubbard model to investigate the properties of the charge- and spin-density-wave phases in the presence of a nearest-neighbors repulsion term in the framework of the slave-boson technique. We show that, contrary to Hartree–Fock results, an instablity may occur for sufficiently high values of the Hubbard repulsion, both in the spin- and charge-density-wave phase, which makes the system discontinuously jump to a phase with a smaller or zero wave amplitude. The limits of applicability of our approach are discussed and our results are compared with previous numerical analysis. The phase diagram of the model at half-filling is determined.

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