We present our theoretical study of the single-particle spectral function in two-dimensonal cuprates by using numerically exact diagonaliation method on small clusters of the extended t-J model containing long-range hopping matrix elements. For a set of the parameter vaues, the calculated spectral function systematically explains the angle-resolved photoemission spectroscopy (ARPES) data for Bi_2Sr_2CaCu_2O_(3+ delta ). For La(2-x)Sr_xCuO_4 (LSCO), it is found that slightly smaller values of long-range hoppings are necessary for understanding an observed change of the fermi surface topology with x. In addition, the dramatic suppression of spectral wwight along (0,0)-( pi , pi ) direction observed in under-doped LSCO is found to be explained by introducing an additional potential for holes which stabilizes vertical charge stripes.
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