title: Hall-plot of the phase diagram for Ba(Fe1-xCox)2As2.
abstract: The Hall effect is a powerful tool for investigating carrier type and density. For single-band materials, the Hall coefficient is traditionally expressed simply by , where e is the charge of the carrier, and n is the concentration. However, it is well known that in the critical region near a quantum phase transition, as it was demonstrated for cuprates and heavy fermions, the Hall coefficient exhibits strong temperature and doping dependencies, which can not be described by such a simple expression, and the interpretation of the Hall coefficient for Fe-based superconductors is also problematic. Here, we investigate thin films of Ba(Fe1-xCox)2As2 with compressive and tensile in-plane strain in a wide range of Co doping. Such in-plane strain changes the band structure of the compounds, resulting in various shifts of the whole phase diagram as a function of Co doping. We show that the resultant phase diagrams for different strain states can be mapped onto a single phase diagram with the Hall number. This universal plot is attributed to the critical fluctuations in multiband systems near the antiferromagnetic transition, which may suggest a direct link between magnetic and superconducting properties in the BaFe2As2 system.
authors.affiliation: Department of Crystalline Materials Science, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan.|IFW Dresden, P.O. Box 270116, 01171 Dresden, Germany.
authors.forename: Kazumasa
authors.initials: K
authors.lastname: Iida
authors.affiliation: Department of Crystalline Materials Science, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan.|IFW Dresden, P.O. Box 270116, 01171 Dresden, Germany.
authors.forename: Vadim
authors.initials: V
authors.lastname: Grinenko
authors.affiliation: IFW Dresden, P.O. Box 270116, 01171 Dresden, Germany.|Dresden University of Technology, Faculty for Natural Science and Mathematics, 01062 Dresden, Germany.
authors.forename: Fritz
authors.initials: F
authors.lastname: Kurth
authors.affiliation: Central Research Institute of Electric Power Industry, 2-6-1 Nagasaka, Yokosuka, Kanagawa 240-0196, Japan.
authors.forename: Ataru
authors.initials: A
authors.lastname: Ichinose
authors.affiliation: Central Research Institute of Electric Power Industry, 2-6-1 Nagasaka, Yokosuka, Kanagawa 240-0196, Japan.
authors.forename: Ichiro
authors.initials: I
authors.lastname: Tsukada
authors.affiliation: IFW Dresden, P.O. Box 270116, 01171 Dresden, Germany.|Dresden University of Technology, Faculty for Natural Science and Mathematics, 01062 Dresden, Germany.
authors.forename: Eike
authors.initials: E
authors.lastname: Ahrens
authors.affiliation: Dresden University of Technology, Faculty for Natural Science and Mathematics, 01062 Dresden, Germany.
authors.forename: Aurimas
authors.initials: A
authors.lastname: Pukenas
authors.affiliation: Dresden University of Technology, Faculty for Natural Science and Mathematics, 01062 Dresden, Germany.
authors.forename: Paul
authors.initials: P
authors.lastname: Chekhonin
authors.affiliation: Dresden University of Technology, Faculty for Natural Science and Mathematics, 01062 Dresden, Germany.
authors.forename: Werner
authors.initials: W
authors.lastname: Skrotzki
authors.affiliation: IFW Dresden, P.O. Box 270116, 01171 Dresden, Germany.
authors.forename: Angelika
authors.initials: A
authors.lastname: Teresiak
authors.affiliation: IFW Dresden, P.O. Box 270116, 01171 Dresden, Germany.
authors.forename: Ruben
authors.initials: R
authors.lastname: Hühne
authors.affiliation: IFW Dresden, P.O. Box 270116, 01171 Dresden, Germany.
authors.forename: Saicharan
authors.initials: S
authors.lastname: Aswartham
authors.affiliation: IFW Dresden, P.O. Box 270116, 01171 Dresden, Germany.|Dresden University of Technology, Faculty for Natural Science and Mathematics, 01062 Dresden, Germany.
authors.forename: Sabine
authors.initials: S
authors.lastname: Wurmehl
authors.affiliation: IFW Dresden, P.O. Box 270116, 01171 Dresden, Germany.
authors.forename: Ingolf
authors.initials: I
authors.lastname: Mönch
authors.affiliation: IFW Dresden, P.O. Box 270116, 01171 Dresden, Germany.|Karlsruhe Institute of Technology, Institute for Technical Physics, Hermann von Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.
authors.forename: Manuela
authors.initials: M
authors.lastname: Erbe
authors.affiliation: IFW Dresden, P.O. Box 270116, 01171 Dresden, Germany.|Karlsruhe Institute of Technology, Institute for Technical Physics, Hermann von Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Hänisch
authors.affiliation: Karlsruhe Institute of Technology, Institute for Technical Physics, Hermann von Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Holzapfel
authors.affiliation: IFW Dresden, P.O. Box 270116, 01171 Dresden, Germany.
authors.forename: Stefan-Ludwig
authors.initials: SL
authors.lastname: Drechsler
authors.affiliation: IFW Dresden, P.O. Box 270116, 01171 Dresden, Germany.
authors.forename: Dmitri V
authors.initials: DV
authors.lastname: Efremov