QUASI-PARTICLE DISPERSION OF SR2CUO2CL2

Recent angle resolved photoemission (ARPES) measurements for the insul ating cuprate Sr2CuO2Cl2 have provided the first experimental data whi ch can be directly compared to the (theoretically) well-studied proble m of a single hole propagating in an antiferromagnet. Some discrepanci es withthe familiar 2D t - J model were observed. Here we discuss a co mparison between the ARPES results and the quasiparticle dispersion of both (i) the extended t - t' - J Hamiltonian and (ii) the three-band Hubbard model.