SYSTEMATICS OF THE PHOTOEMISSION SPECTRAL-FUNCTION OF CUPRATES - INSULATORS AND HOLE-DOPED AND ELECTRON-DOPED SUPERCONDUCTORS

Angle-resolved photoemission studies on Sr2CuO2Cl2 at a temperature be low its Neel temperature reveal detailed momentum dependent line shape changes as a function of wave vector. While a sharp quasiparticlelike peak is observed near (pi/2, pi/2), broad peaks are observed near (pi , 0). Additional second and third neighbor hopping terms must be added to the t-J Hamiltonian to account for both the dispersion and the lin e shape. It is found that this Hamiltonian can be used to explain the measured momentum dependent spectral function for hole-doped materials , both underdoped and overdoped, as well as electron-doped materials.