Spectral behavior of the electronic states of bilayer cuprate systems using a slave fermion approach

Abstract

The spectral function for electrons in the normal state of a bilayer cuprate is calculated by employing a slave fermion approach. The electron correlations in the CuO₂ layers in these cuprates are described by a t-J model, and the electronic coupling between the two CuO₂ layers within the same unit cell is introduced via a hopping matrix element (t_⊥) and an exchange interaction (J_⊥). The spectral function is calculated for different values of the hole concentration, temperature, and anisotropy at various values of the momentum (k_x,k_y). It is found that the bilayer coupling (t_⊥) significantly affects the behavior of the spectral function. The spectral function around the momentum value (π, 0) for a coupled bilayer cuprate shows a peak much sharper than that for a system of uncoupled layers. Our calculation also suggests a splitting of electronic states of the bilayer cuprates along the (π, 0) direction for the heavily overdoped regime. Calculations of the imaginary part of the self-energy Σ₁'(k,ω) for a bilayer system have also been presented. It is found that Σ₁'(k,ω) depends strongly on the momentum and shows a ω^α dependence on energy with 1.2<α<1.5 for values of the parameters t and J considered in the present calculations.