Energy bands, fermi surface and density of states in the superconducting state of La 2−xSr xCuO 4

Abstract

Energy bands, Fermi surface and density of states in the superconducting states of La 2- x Sr x CuO 4 are derived by solving approximately the coupled spin-Fermion type effective Hamiltonian proposed by Kamimura and Suwa, based on their “spin-fixed Fermi liquid” model. The present results are consistent with the experimental results of the Mott-Hubbard insulator for La 2CuO 4. Unique feature of the flat dispersion of the highest occupied band, the extremely flat shape of Fermi surface, and a sharp peak at x≈ 0.2 in the density of states should be tested by experiments.