Evolution of the Fermi surface geometry in high Tc superconductors: from small hole pockets to a large tight binding Fermi surface

Abstract

The evolution of the Fermi surface geometry in high T c superconductors is studied within the t– J model with increasing hole doping concentration. The drastic change of the Fermi surface geometry from small hole pockets to a large tight binding Fermi surface happens at about 10% doping concentration much faster than a rigid band picture predicts. This rapid change is caused by the strong dynamical effect of interacting doped holes on the spin–polaron quasiparticle band. The decreasing spectral weight of the quasiparticle band is compensated by the significant band flattening near the Fermi energy for an optimal doping case so that the high density of states is still preserved in agreement with experiments.