We report angle-resolved photoemission spectra (ARPES) from the Fermi energy
(EF​) over a large area of the (kx​,ky​) plane using 21.2 eV and 32 eV
photons in two distinct polarizations from an optimally doped single crystal of
Bi2​Sr2​CaCu2​O8+δ​ (Bi2212), together with extensive
first-principles simulations of the ARPES intensities. The results display a
wide-ranging level of accord between theory and experiment and clarify how
myriad Fermi surface (FS) maps emerge in ARPES under various experimental
conditions. The energy and polarization dependences of the ARPES matrix element
help disentangle primary contributions to the spectrum due to the pristine
lattice from those arising from modulations of the underlying tetragonal
symmetry and provide a route for separating closely placed FS sheets in low
dimensional materials.Comment: submitted to PR