title: Site specific spin dynamics in BaFe2As2: tuning the ground state by orbital differentiation.
abstract: The role of orbital differentiation on the emergence of superconductivity in the Fe-based superconductors remains an open question to the scientific community. In this investigation, we employ a suitable microscopic spin probe technique, namely Electron Spin Resonance (ESR), to investigate this issue on selected chemically substituted BaFe2As2 single crystals. As the spin-density wave (SDW) phase is suppressed, we observe a clear increase of the Fe 3d bands anisotropy along with their localization at the FeAs plane. Such an increase of the planar orbital content is interestingly independent of the chemical substitution responsible for suppressing the SDW phase. As a consequence, the magnetic fluctuations in combination with this particular symmetry of the Fe 3d bands are propitious ingredients for the emergence of superconductivity in this class of materials.
authors.affiliation: 1] Instituto de Física "Gleb Wataghin", UNICAMP, Campinas-SP, 13083-859, Brazil [2] University of California, Irvine, California 92697-4574, USA.
authors.forename: P F S
authors.initials: PF
authors.lastname: Rosa
authors.affiliation: Instituto de Física "Gleb Wataghin", UNICAMP, Campinas-SP, 13083-859, Brazil.
authors.forename: C
authors.initials: C
authors.lastname: Adriano
authors.affiliation: Instituto de Física "Gleb Wataghin", UNICAMP, Campinas-SP, 13083-859, Brazil.
authors.forename: T M
authors.initials: TM
authors.lastname: Garitezi
authors.affiliation: University of California, Irvine, California 92697-4574, USA.
authors.forename: T
authors.initials: T
authors.lastname: Grant
authors.affiliation: University of California, Irvine, California 92697-4574, USA.
authors.forename: Z
authors.initials: Z
authors.lastname: Fisk
authors.affiliation: Instituto de Física "Gleb Wataghin", UNICAMP, Campinas-SP, 13083-859, Brazil.
authors.forename: R R
authors.initials: RR
authors.lastname: Urbano
authors.affiliation: Instituto de Física "Gleb Wataghin", UNICAMP, Campinas-SP, 13083-859, Brazil.
authors.forename: P G
authors.initials: PG
authors.lastname: Pagliuso