Systematics of the photoemission spectral function of cuprates: Insulators and hole- and electron-doped superconductors

Angle-resolved photoemission studies on Sr2CuO2Cl2 at a temperature below 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 line 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.