Theory on vortex states in anisotropic superconductors with strong correlation
Project/Area Number  10640334 
Research Category 
GrantinAid for Scientific Research (C).

Section  一般 
Research Field 
固体物性II(磁性・金属・低温)

Research Institution  The University of Tokyo 
Principal Investigator 
OGATA Masao Department of Applied Physics, Nagoya University, associate professor, 大学院・統合文化研究科, 助教授 (60185501)

CoInvestigator(Kenkyūbuntansha) 
田仲 由喜夫 名古屋大学, 大学院・工学研究科, 助教授 (40212039)

Project Fiscal Year 
1998 – 1999

Project Status 
Completed(Fiscal Year 1999)

Budget Amount *help 
¥3,300,000 (Direct Cost : ¥3,300,000)
Fiscal Year 1999 : ¥1,200,000 (Direct Cost : ¥1,200,000)
Fiscal Year 1998 : ¥2,100,000 (Direct Cost : ¥2,100,000)

Keywords  strong correlation / vortex in anisotropic super conductors / tJ model / highTc superconductivity / 電子相関 / 異方的超伝導体の磁束 / tJモデル / 高温超伝導 
Research Abstract 
We studied theoretically ab014t the anomalous behaviors of the electronic states near the vortex cores as well as the relating phenomena, using the twodimensional tJ model in which the anisotropic superconductivity with strong correlation is realized. For this purpose we developed the programs for numerical calculations and applied them to various cases. The obtained results are summarized as follows : 1. We studied the electronic states near the vortex core of highTィイD2cィエD2 superconductors by applying the Gutzwiller approximation to the Bogoliubovde Gennes equations. As a result, we found possibilities that an extended swave component and antiferromagnetic correlations are induced inside the core when the doping rate is small. 2. We examined the ground state of the twodimensional tJ model using the variational Monte Carlo simulation which was extended for the case with antiferromagnetic order parameters. It was found that the dwave superconductivity and antiferromagnetism coexist near half filling. 3. We extended the Gutzwiller approximation for studying the strong correlation, by comparing the numerical results and analytical methods. The obtained extended approximation can be easily applied to the Bogoliubovde Gennes equations. We used this method for the cases with antiferromagnetic correlations. 4. We studied the electronic states near the boundary and impurities in the tJ model, which are closely related to the vortex problem. Some new features were found about the dependence of the surface states on the shape of the Fermi surface and about the magnetic impurities. 5. We investigated the stripe state in which the antiferromagnetism and dwave superconductivity coexist using the extended Gutzwiller approximation. It was found that some impurity pinning potential is necessary to stabilize the stripe states.

Report
(4results)
Research Output
(19results)