title: Sign-reversal of the in-plane resistivity anisotropy in hole-doped iron pnictides.
abstract: Unconventional superconductivity usually originates from several strongly coupled degrees of freedom, such as magnetic, charge and elastic. A highly anisotropic electronic phase, not driven by lattice degrees of freedom, has been proposed in some of these superconductors, from cuprates to iron-based compounds. In the iron pnictide BaFe2As2, this nematic phase arises in the paramagnetic phase and is present for wide doping and temperature ranges. Here we probe the in-plane electronic anisotropy of electron- and hole-doped BaFe2As2 compounds. Unlike other materials, the resistivity anisotropy behaves very differently for electron- and hole-type dopants and even changes sign on the hole-doped side. This behaviour is explained by Fermi surface reconstruction in the magnetic phase and spin-fluctuation scattering in the paramagnetic phase. This unique transport anisotropy unveils the primary role played by magnetic scattering, demonstrating the close connection between magnetism, nematicity and unconventional superconductivity.
authors.affiliation: The Ames Laboratory, Ames, Iowa 50011, USA.
authors.forename: E C
authors.initials: EC
authors.lastname: Blomberg
authors.forename: M A
authors.initials: MA
authors.lastname: Tanatar
authors.forename: R M
authors.initials: RM
authors.lastname: Fernandes
authors.forename: I I
authors.initials: II
authors.lastname: Mazin
authors.forename: Bing
authors.initials: B
authors.lastname: Shen
authors.forename: Hai-Hu
authors.initials: HH
authors.lastname: Wen
authors.forename: M D
authors.initials: MD
authors.lastname: Johannes
authors.forename: J
authors.initials: J
authors.lastname: Schmalian
authors.forename: R
authors.initials: R
authors.lastname: Prozorov