Orbital characters determined from Fermi surface intensity patterns using angle-resolved photoemission spectroscopy

摘要

In order to determine the orbital characters on the various Fermi surface pockets of the Fe-based superconductors Ba_(0.6)K_(0.4)Fe_2As_2 and FeSe_(0.45)Te_(0.55), we introduce a method to calculate photoemission matrix elements. We compare our simulations to experimental data obtained with various experimental configurations of beam orientation and light polarization. We show that the photoemission intensity patterns revealed from angle-resolved photoemission spectroscopy measurements of Fermi surface mappings and energy-momentum plots along high-symmetry lines exhibit asymmetries carrying precious information on the nature of the states probed, information that is destroyed after the data symmetrization process often performed in the analysis of angle-resolved photoemission spectroscopy data. Our simulations are consistent with Fermi surfaces originating mainly from the d_(xy), d_(xz), and d_(yz) orbitals in these materials.