Influence of C-Axis Inter Unit Cell Resonant Tunneling on the Spectral Function in Bilayer Cuprates

Abstract

The role of intra unit cell coupling along with inter unit cell resonant tunneling between the copper-oxygen planes on the electronic spectral function in normal state of bilayer high T_c cuprates like Bi₂Sr₂CaCu₂O_8+x is investigated. The Hubbard model including terms representing hopping between the planes within the unit cell, and resonant tunneling between the planes in two adjoining cells is used along with the Green’s function equation of motion approach to obtain an expression of spectral function. The spectral function at (&#960,0) point of the Brillouin zone is numerically calculated. It is found that the intra unit cell coupling lead to splitting of spectral peak especially close to (&#960,0) point, while the inter unit cell resonant tunneling lead to a broadening in the spectral function and suppression of bilayer splitting in the normal state. In the presence of finite electron correlations the inter unit cell tunneling induce strong broadening in the spectral features. The electron correlations and inter unit cell tunneling is important in determining the shape of the spectral function in doped bilayer cuprates. These results are viewed in terms of the existing ARPES measurements on bilayer cuprates.