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| VOLUME 101 (2015) | ISSUE 6 | PAGE 446 |
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Occurrence of flat bands in strongly correlated Fermi systems and high-Tc superconductivity of electron-doped compounds
V. A. Khodela,b, J. W. Clarkb,c, K. G. Popovd,e, V. R. Shaginyanf,g
aNational Research Centre "Kurchatov Institute", 123182 Moscow, Russia bMcDonnell Center for the Space Sciences and Department of Physics, Washington University, MO 63130 St. Louis,, USA cCentro de Ciências Matemáticas, Universidade de Madeira, 9000-390 Funchal, Madeira, Portugal dKomi Science Center UD of the RAS, 167982 Syktyvkar, Russia eDepartment of Physics, St.Petersburg State University, 199034 St. Petersburg, Russia fKonstantinov Petersburg Nuclear Physics Institute of the RAS, National Research Centre "Kurchatov Institute", 188300 Gatchina, Russia gClark Atlanta University, GA 30314 Atlanta, USA
Abstract
We consider a class of strongly correlated Fermi systems that exhibit an interaction-induced flat band pinned to the Fermi surface, and generalize the Landau strategy to accommodate a flat band and apply the more comprehensive theory to electron systems of solids. The non-Fermi-liquid behavior that emerges is compared with relevant experimental data on heavy-fermion metals and electron-doped high-Tc compounds. We elucidate how heavy-fermion metals have extremely low superconducting transition temperature Tc, its maximum reached in the heavy-fermion metal CeCoIn5 does not exceed 2.3 K, and explain the enhancement of Tc observed in high-Tc superconductors. We show that the coefficient A1 of the T-linear resistivity scales with Tc, in agreement with the experimental behavior uncovered in the electron-doped materials. We have also constructed schematic temperature-doping phase diagram of the copper oxide superconductor La2-xCexCuO4 and explained the doping dependence of its resistivity. |