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

Abstract

In order to explore the reason why the single-layered cuprates, La${}_{2-x}$(Sr/Ba)${}_x$CuO${}_4$ ($T_c\simeq$ 40K) and HgBa${}_2$CuO${}_{4+\delta }$ ($T_c\simeq$ 90K), have such a significant difference in $T_c$, we study a two-orbital model that incorporates the $d_{z^2}$ orbital on top of the $d_{x^2-y^2}$ orbital. It is found, with the fluctuation exchange approximation, that the $d_{z^2}$ 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 $T_c$ in the cuprates.

4 pages, 4 figures. Final version published in Phys. Rev. Lett

References in corpus (2)

• Effect of Structural Parameters on Superconductivity in Fluorine-Free LnFeAsO1-y (Ln=La,Nd)
• Combined density-functional and dynamical cluster quantum Monte Carlo calculations for three-band Hubbard models for hole-doped cuprate superconductors

Cited by in corpus (2)

• Unraveling the Nature of Charge Excitations in La${}_2$CuO${}_4$ with Momentum-Resolved Cu $K$-edge Resonant Inelastic X-ray Scattering
• d_{3z^2-r^2} Orbital in high-Tc cuprates: Excitonic spectrum, metal-insulator phase diagram, optical conductivity and orbital character of doped holes