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Phys. Rev. Lett. 105, 057003 (2010) [4 pages]

Two-Orbital Model Explains the Higher Transition Temperature of the Single-Layer Hg-Cuprate Superconductor Compared to That of the La-Cuprate Superconductor

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Hirofumi Sakakibara1, Hidetomo Usui1, Kazuhiko Kuroki1,4, Ryotaro Arita2,4,5, and Hideo Aoki3,4
1Department of Applied Physics and Chemistry, The University of Electro-Communications, Chofu, Tokyo 182-8585, Japan
2Department of Applied Physics, The University of Tokyo, Hongo, Tokyo 113-8656, Japan
3Department of Physics, The University of Tokyo, Hongo, Tokyo 113-0033, Japan
4JST, TRIP, Sanbancho, Chiyoda, Tokyo 102-0075, Japan
5JST, CREST, Hongo, Tokyo 113-8656, Japan

Received 3 March 2010; published 30 July 2010

In order to explore the reason why the single-layered cuprates, La2-x(Sr/Ba)xCuO4 (Tc≃40  K) and HgBa2CuO4+δ (Tc≃90  K) have such a significant difference in Tc, we study a two-orbital model that incorporates the dz2 orbital on top of the dx2-y2 orbital. It is found, with the fluctuation exchange approximation, that the dz2 orbital contribution to the Fermi surface, which is stronger in the La system, works against d-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 Tc in the cuprates.

© 2010 The American Physical Society

URL:
http://link.aps.org/doi/10.1103/PhysRevLett.105.057003
DOI:
10.1103/PhysRevLett.105.057003
PACS:
74.62.Bf, 74.20.-z, 74.72.-h
 
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