Superconductivity and antiferromagnetism in the phase diagram of the frustrated Hubbard model within a variational study

✍ Scribed by Kenji Kobayashi; Hisatoshi Yokoyama

• Publisher: Elsevier Science
• Year: 2010
• Tongue: English
• Weight: 307 KB
• Volume: 470
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/j.physc.2010.05.041

✦ Synopsis

The interplay between antiferromagnetism (AF) and superconductivity (SC) in cuprates is studied for the two-dimensional Hubbard model with a diagonal transfer t 0 , using a variational Monte Carlo method. Optimizing an improved function for strongly correlated values of U/t, we construct phase diagrams in the d (doping rate)-t 0 /t space. It is found that the stable state is sensitive to the value of model parameters: For the extremely large values of U/t, a coexisting state is realized for t 0 /t J À0.15, whose range of doping rate extends as t 0 /t increases. In contrast, for t 0 /t = À0.3, AF and SC states are mutually exclusive, and a coexisting state does not appear. As U/t decreases, the area of pure AF extends, and that of coexisting state shrinks. As a result, the coexisting state disappears for t 0 /t = À0.15 and U/t = 12, probable values for holedoped cuprates. Compared with the t-J model, the Hubbard model has richer phases.