Emergence of multiple Fermi surface maps in angle-resolved photoemission from Bi2Sr2CaCu2O8+delta

We report angle-resolved photoemission spectra (ARPES) for emission from the Fermi energy (E-F) over a large area of the (k(x),k(y)) plane using 21.2 and 32 eV photon energies in two distinct polarizations from an optimally doped single crystal of Bi2Sr2CaCu2O8+delta (Bi2212), together with extensive first-principles simulations of the ARPES intensities. The results display a wide-ranging level of accord between theory and experiment, demonstrating that the ARPES matrix elements can produce a striking variety of Fermi surface maps, especially in the presence of secondary features arising from modulations of the underlying tetragonal system. Our analysis demonstrates how the energy and polarization dependency of the ARPES matrix element can help to disentangle the primary contributions to the spectrum from the secondary features and indicates that secondary features reflect a direct modulation of the CuO2 planes.