Magnetoresistance scaling, disorder, `hot spots' and the origin of $T$-linear resistivity in BaFe$_2$(As$_{1-x}$P$_x$)$_2$

TL;DR

This study investigates the origin of T-linear resistivity in BaFe$_2$(As$_{1-x}$P$_x$)$_2$ by analyzing magnetoresistance scaling and hot spots on the Fermi surface, linking antiferromagnetic fluctuations to electronic transport properties.

Contribution

The paper introduces an orbital model incorporating hot spots and anisotropic scattering to explain magnetoresistance scaling and its relation to T-linear resistivity in iron-based superconductors.

Findings

Magnetoresistance is dominated by hot spots on the Fermi surface.

Temperature-magnetic field scaling relations are consistent with experimental data.

Hot spots linked to antiferromagnetic criticality explain T-linear resistivity.

Abstract

The scaling of $H$-linear magnetoresistance in field and temperature was measured in under-doped (x = 0.19) and optimally-doped (x=0.31)~BaFe$_2$(As$_{1-x}$P$_x$)$_2$. We analyze the data based on an orbital model in the presence of strongly anisotropic quasiparticle spectra and scattering time due to antiferromagnetism. The magnetoresistance is dominated by the properties of small regions of the Fermi surface called `hot spots' where antiferromagnetic excitations induce a large quasiparticle scattering rate. Approximate temperature-magnetic field scaling relations are derived and shown to be consistent with the experimental data. We argue that these results link the origin of linear-in-temperature resistivity to hot spots arising from an antiferromagnetic critical point, and magnetoresistance measurements provide a route to quantify this link.