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I will study three different cases of ARPES of HTS. - BISCO with glide plane symmetry, - LSCCO with doping from insulater to strange-metal, and - Bi-bands in BISCO. Spectroscopy (ARPES) measurements of Bismuth-based high t_c superconductors (HTS) a shadow Fermi surface is seen. We derive photoelectron selection rules for ARPES intensity along the glide plane in orthorhombic Bi2Sr2CaCu2O8+ (Bi2212). These selection rules explain the reversed intensity behavior of the shadow and the main band of the material as a natural consequence of the variating representation of the final state as a function of k_{||}. ARPES measurements find that LDA-like Quasi Particles (QP) persits in LASCO over a wide range of binding energy and at all dopings x. We have shown that the dispersion of QP near Fermi level are remarkably LDA-like. Now we will test LDA prediction of doping and energy dependencies of I(E). We show that the experimental spectra shifted by E_F all show good scaling amd the envelope is in good agreement with the LDA calcucation, except for the nodal direction in the first Brillouin zone. Details of these determination is discussed and special consideration is given surface states. The absence of Bi-related spectral features in BISCO spectra round the M-point is one of the mysteries of ARPES of HTS. We have search possible photon energy dependence of Bi-related features and find out that when computational surface resonances are removed a cross section for the Bi pocket is very small over wide photon energy range and our prediction is that they will not be detected with present measuring technique. |
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