Abstract
In order to explore the reason why the single-layered cuprates, () and () have such a significant difference in , we study a two-orbital model that incorporates the orbital on top of the orbital. It is found, with the fluctuation exchange approximation, that the orbital contribution to the Fermi surface, which is stronger in the La system, works against -wave superconductivity, thereby dominating over the effect of the Fermi surface shape. The result resolves the long-standing contradiction between the theoretical results on Hubbard-type models and the experimental material dependence of in the cuprates.
- Received 3 March 2010
DOI:https://doi.org/10.1103/PhysRevLett.105.057003
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