Occurrence of flat bands in strongly correlated Fermi systems and high-$T_c$ superconductivity of electron-doped compounds

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-$T_c$ compounds. We elucidate how heavy-fermion metals have extremely low superconducting transition temperature $T_c$, its maximum reached in the heavy-fermion metal CeCoIn${}_5$ does not exceed 2.3 K, and explain the enhancement of $T_c$ observed in high-$T_c$ superconductors. We show that the coefficient $A_1$ of the $T$-linear resistivity scales with $T_c$, 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 $\mathrm{L}{\mathrm{a}}_{2-\mathrm{x}}\mathrm{C}{\mathrm{e}}_{\mathrm{x}}\mathrm{Cu}{\mathrm{O}}_4$ and explained the doping dependence of its resistivity.

6 pages, 2 figures, revised and published by JETP Lett

References in corpus (7)

• A Non-Fermi Liquid from a Charged Black Hole; A Critical Fermi Ball
• Lifshitz critical point in the cuprate superconductor YBa2Cu3Oy from high-field Hall effect measurements
• Scaling Behavior of Heavy Fermion Metals
• Nonvanishing Energy Scales at the Quantum Critical Point of CeCoIn5
• Flat band in the core of topological defects: bulk-vortex correspondence in topological superfluids with Fermi points
• Challenging Magnetic Field Dependence of the Residual Resistivity of the Heavy-Fermion Metal CeCoIn5
• Merging of Landau levels in a strongly-interacting two-dimensional electron system in silicon

Cited by in corpus (1)

• Temperature and doping induced instabilities of the repulsive Hubbard model on Lieb lattice