Matrix element effects in the angle-resolved photoemission spectrum of BISCO

We report first-principles angle-resolved photointensity (ARPES) simulation s in Bi2212 in order to assess the importance of matrix element effects in the ARPES spectra. Our calculations properly account for the photoemission process and include full crystal wavefunctions of the initial and final sta tes in the presence of the surface. The spectral weight of the ARPES featur e associated with the CuO2 plane bands is found to be strongly anisotropic in the (k(x), k(y)) plane. These results indicate that the relationship bet ween the ARPES intensities and the underlying electronic structure can be q uite complicated and that caution should be exercised in interpreting detai led features of the ARPES intensities in terms of the properties of the the oretical one-particle spectral density functions. (C) 1998 Elsevier Science Ltd. All rights reserved.