We present a theory for the photon energy and polarization dependence of ARPES intensities from the CuO2 plane in the framework of strong correlation models. We show that for electric field vector in the CuO2 plane the `radiation characteristics' of the O2pσ and Cu3dx2−y2 orbitals are strongly peaked along the CuO2 plane, i.e. most photoelectrons are emitted at grazing angles. This suggests that surface states play an important role in the observed ARPES spectra, consistent with recent data from Sr2CuCl2O2. We show that a combination of surface state dispersion and Fano resonance between surface state and the continuum of LEED-states may produce a precipitous drop in the observed photoelectron current as a function of in-plane momentum, which may well mimic a Fermi-surface crossing. This effect may explain the simultaneous `observation' of a hole-like and an electron-like Fermi surfaces in Bi2212 at different photon energies. We show that by suitable choice of photon polarization one can on one hand `focus' the radiation characteristics of the in-plane orbitals towards the detector and on the other hand make the interference between partial waves from different orbitals `more constructive'.
@article{arxiv.cond-mat/0109036,
title = {Theory of ARPES intensities from the CuO$_2$ plane},
author = {C. Dahnken and R. Eder},
journal= {arXiv preprint arXiv:cond-mat/0109036},
year = {2013}
}