scholarly journals Superconductivity in the two-dimensional Hubbard model: Gutzwiller wave function solution

2013 ◽  
Vol 88 (11) ◽  
Author(s):  
Jan Kaczmarczyk ◽  
Jozef Spałek ◽  
Tobias Schickling ◽  
Jörg Bünemann
Keyword(s):  
Wave Function ◽  
Hubbard Model ◽  
Two Dimensional ◽  
Function Solution

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.

scholarly journals On the Kinetic Energy Driven Superconductivity in the Two-Dimensional Hubbard Model

2021 ◽  
Vol 6 (1) ◽  
pp. 12
Author(s):  
Takashi Yanagisawa ◽  
Kunihiko Yamaji ◽  
Mitake Miyazaki
Keyword(s):  
Wave Function ◽  
Kinetic Energy ◽  
Hubbard Model ◽  
High Temperature Superconductivity ◽  
Repulsive Interaction ◽  
Two Dimensional ◽  
Condensation Energy ◽  
Energy Effect ◽  
Correlation Operator ◽  
Correlated Electron

We investigate the role of kinetic energy for the stability of superconducting state in the two-dimensional Hubbard model on the basis of an optimization variational Monte Carlo method. The wave function is optimized by multiplying by correlation operators of site off-diagonal type. This wave function is written in an exponential-type form given as ψλ=exp(−λK)ψG for the Gutzwiller wave function ψG and a kinetic operator K. The kinetic correlation operator exp(−λK) plays an important role in the emergence of superconductivity in large-U region of the two-dimensional Hubbard model, where U is the on-site Coulomb repulsive interaction. We show that the superconducting condensation energy mainly originates from the kinetic energy in the strongly correlated region. This may indicate a possibility of high-temperature superconductivity due to the kinetic energy effect in correlated electron systems.

The pairing symmetries in the two-dimensional Hubbard model

2021 ◽  
pp. 127153
Author(s):  
Ke Liu ◽  
Shuhui Yang ◽  
Weiqi Li ◽  
Tao Ying ◽  
Jianqun Yang ◽  
...  
Keyword(s):  
Hubbard Model ◽  
Two Dimensional ◽  
Pairing Symmetries

scholarly journals Spin diffusion and spin conductivity in the two-dimensional Hubbard model

2021 ◽  
Vol 103 (15) ◽  
Author(s):  
Martin Ulaga ◽  
Jernej Mravlje ◽  
Jure Kokalj
Keyword(s):  
Hubbard Model ◽  
Spin Diffusion ◽  
Two Dimensional
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