scholarly journals Numerical results on the short-range spin correlation functions in the ground state of the two-dimensional Hubbard model

2017 ◽  
Vol 96 (7) ◽  
Author(s):  
Mingpu Qin ◽  
Hao Shi ◽  
Shiwei Zhang
Keyword(s):  
Hubbard Model ◽  
Ground State ◽  
Correlation Functions ◽  
Short Range ◽  
Spin Correlation ◽  
Numerical Results ◽  
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′.

Spin–Spin Correlations in Site Disordered ±J 2D Ising Spin Glasses

1998 ◽  
Vol 09 (05) ◽  
pp. 685-691
Author(s):  
B. Kawecka-Magiera ◽  
A. Z. Maksymowicz ◽  
M. Kowal ◽  
K. Kulakowski
Keyword(s):  
Correlation Functions ◽  
Spin Glasses ◽  
Interatomic Distance ◽  
Spin Correlation ◽  
Two Dimensional ◽  
Spin Correlations ◽  
Ising Spin ◽  
Bond System ◽  
Random Site

Spin–spin correlation functions <S(0)S(R)> as dependent on interatomic distance R are studied in the random-site two-dimensional Ising S=1/2 ±J system. Oscillations of the correlation functions are found, which is not a case in the random-bond system.

Recent Numerical Results on the Two-Dimensional Hubbard Model

1989 ◽  
pp. 390-390
Author(s):  
S. Sorella ◽  
S. Baroni ◽  
R. Car ◽  
M. Parrinello ◽  
A. Parola ◽  
...  
Keyword(s):  
Hubbard Model ◽  
Numerical Results ◽  
Two Dimensional

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.

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