High T_c superconductivity due to coexisting wide and narrow bands: A fluctuation exchange study on the Hubbard ladder as a test case

Kazuhiko Kuroki, Takafumi Higashida, Ryotaro Arita

We propose that when the Fermi level lies within a wide band and also lies close to but not within a coexisting narrow band, high $T_c$ superconductivity may take place due to the…