Magnetoresistance Scaling and the Origin of H -Linear Resistivity in BaFe2 (As1-x Px)2

Abstract

We explore field and temperature scaling of magnetoresistance in underdoped (x=0, x=0.19) and optimally doped (x=0.31) samples of the high-temperature superconductor BaFe2(As1-xPx)2. In all cases, the magnetoresistance is H linear at high fields. We demonstrate that the data can be explained by an orbital model in the presence of strongly anisotropic quasiparticle spectra and scattering time due to antiferromagnetism. In optimally doped samples, the magnetoresistance is controlled by the properties of small regions of the Fermi surface called "hot spots,"where antiferromagnetic excitations induce a large quasiparticle scattering rate. The anisotropic scattering rate results in hyperbolic H/T magnetoresistance scaling, which competes with the more conventional Kohler scaling. We argue that these results constitute a coherent picture of magnetotransport in BaFe2(As1-xPx)2, which links the origin of H-linear resistivity to antiferromagnetic hot spots. Implications for the T-linear resistivity at zero field are discussed.