Phase diagram of the two-dimensional disordered Hubbard model in the Hartree-Fock approximation

1993 ◽  
Vol 47 (2) ◽  
pp. 1126-1129 ◽  
Author(s):  
C. Dasgupta ◽  
J. W. Halley
Keyword(s):  
Phase Diagram ◽  
Hubbard Model ◽  
Two Dimensional ◽  
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.

Phase diagram of cuprate high-temperature superconductors based on the optimization Monte Carlo method

2020 ◽  
Vol 34 (19n20) ◽  
pp. 2040046
Author(s):  
T. Yanagisawa ◽  
M. Miyazaki ◽  
K. Yamaji
Keyword(s):  
Phase Diagram ◽  
Monte Carlo ◽  
Wave Function ◽  
High Temperature ◽  
Hubbard Model ◽  
Ground State ◽  
State Energy ◽  
High Temperature Superconductivity ◽  
Two Dimensional ◽  
Text Model

It is important to understand the phase diagram of electronic states in the CuO2 plane to clarify the mechanism of high-temperature superconductivity. We investigate the ground state of electronic models with strong correlation by employing the optimization variational Monte Carlo method. We consider the two-dimensional Hubbard model as well as the three-band [Formula: see text]–[Formula: see text] model. We use the improved wave function that takes account of inter-site electron correlation to go beyond the Gutzwiller wave function. The ground state energy is lowered considerably, which now gives the best estimate of the ground state energy for the two-dimensional Hubbard model. The many-body effect plays an important role as an origin of spin correlation and superconductivity in correlated electron systems. We investigate the competition between the antiferromagnetic state and superconducting state by varying the Coulomb repulsion [Formula: see text], the band parameter [Formula: see text] and the electron density [Formula: see text] for the Hubbard model. We show phase diagrams that include superconducting and antiferromagnetic phases. We expect that high-temperature superconductivity occurs near the boundary between antiferromagnetic phase and superconducting one. Since the three-band [Formula: see text]–[Formula: see text] model contains many-band parameters, high-temperature superconductivity may be more likely to occur in the [Formula: see text]–[Formula: see text] model than in single-band models.

THE PHASE DIAGRAM OF THE HUBBARD MODEL

1991 ◽  
Vol 05 (06n07) ◽  
pp. 865-883 ◽  
Author(s):  
M. W. LONG
Keyword(s):  
Phase Diagram ◽  
Hubbard Model ◽  
Exact Results ◽  
Hartree Fock ◽  
Clear Solution

A brief review of the types of ideas which have been used to investigate the phase diagram of the Hubbard model is presented. No clear solution emerges although the competitions at work are established. Hartree-Fock, Gutzwiller's projection, Nagaoka's theorem, Kanamori's paramagnetism, Lieb's exact results and charge-spin separation are the main concepts.

scholarly journals Incommensurate Spin-Density Wave in Two-Dimensional Hubbard Model

2012 ◽  
Vol 190 ◽  
pp. 67-70 ◽  
Author(s):  
M.A. Timirgazin ◽  
Anatoly K. Arzhnikov ◽  
A.V. Vedyayev
Keyword(s):  
Phase Diagram ◽  
Hubbard Model ◽  
Ground State ◽  
Magnetic Phase ◽  
Density Wave ◽  
Spin Density Wave ◽  
Magnetic Phase Diagram ◽  
Two Dimensional ◽  
Magnetic Phases ◽  
Model Relation

We consider the magnetic phase diagram of the two-dimensional Hubbard model ona square lattice.We take into account both spiral and collinear incommensurate magnetic states.The possibility of phase separation of spiral magnetic phases is taken into consideration as well.Our study shows that all the listed phases appear to be the ground state at certain parametersof the model. Relation of the obtained results to real materials, e.g. Cu-based high-temperaturesuperconductors, is discussed.

scholarly journals Emergent BCS regime of the two-dimensional fermionic Hubbard model: Ground-state phase diagram

2015 ◽  
Vol 110 (5) ◽  
pp. 57001 ◽  
Author(s):  
Youjin Deng ◽  
Evgeny Kozik ◽  
Nikolay V. Prokof'ev ◽  
Boris V. Svistunov
Keyword(s):  
Phase Diagram ◽  
Hubbard Model ◽  
Ground State ◽  
Two Dimensional ◽  
Ground State Phase Diagram

MAGNETIC PHASE DIAGRAM OF THE HUBBARD MODEL ON THE AB2 CHAIN

2013 ◽  
Vol 27 (20) ◽  
pp. 1350144
Author(s):  
A. C. NASCIMENTO ◽  
ANDRE M. C. SOUZA
Keyword(s):  
Phase Diagram ◽  
Magnetic Properties ◽  
Hubbard Model ◽  
Function Method ◽  
Magnetic Phase ◽  
Magnetic Phase Diagram ◽  
Electron Interaction ◽  
Hartree Fock ◽  
Band Filling ◽  
Complete Investigation

In this paper, a complete investigation of the magnetic properties of the Hubbard model on the AB2 chain is presented. We evaluate the magnetic phase diagram as a function of the electron–electron interaction and band filling by using the Green's function method within the Hartree–Fock approximation. Our results are in agreement with Lieb's theorem and the system shows ferromagnetic, ferrimagnetic, and paramagnetic phases.

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