title: Mössbauer studies of the superconducting cobalt/nickel-doped BaFe2As2. Whither go the injected electron(s)?
abstract: Mössbauer studies of cobalt- and nickel-doped BaFe(2)As(2) show that the s-electron density at the (57)Fe nuclei, as measured by the isomer shift, is the same as that for the parent BaFe(2)As(2). Apparently, the electron population of the d shell, which shields the s-electron density at the nuclei, remains unchanged. We invoke the involvement of p-orbital hybridization with the d orbital in Fe-As bonding. Furthermore, the shrinkage of the lattice on substitution enhances the As-As sp hybridization, providing a path for the migration of additional electrons. The proposed mechanism is consistent with Hall coefficient and thermoelectric effect measurements.
authors.affiliation: Department of Chemistry, University of North Carolina, Asheville, NC 28804, USA.
authors.forename: Airat
authors.initials: A
authors.lastname: Khasanov
authors.forename: Satish C
authors.initials: SC
authors.lastname: Bhargava
authors.forename: John G
authors.initials: JG
authors.lastname: Stevens
authors.forename: Jianyi
authors.initials: J
authors.lastname: Jiang
authors.forename: Jeremy D
authors.initials: JD
authors.lastname: Weiss
authors.forename: Eric E
authors.initials: EE
authors.lastname: Hellstrom
authors.forename: Amar
authors.initials: A
authors.lastname: Nath