Anisotropic quasiparticle lifetimes in Fe-based superconductors

TL;DR

This paper investigates the anisotropic quasiparticle lifetimes in Fe-based superconductors, revealing how spin and charge fluctuations cause momentum-dependent scattering rates that influence electronic transport properties.

Contribution

It introduces a five-orbital model with RPA calculations to quantify anisotropic scattering rates, linking microscopic interactions to macroscopic transport phenomena.

Findings

Quasiparticle scattering rates are highly anisotropic on Fermi surface sheets.

Anisotropy in scattering and effective mass explains disparities in conductivity and Hall coefficient.

Results qualitatively agree with experimental observations.

Abstract

We study the dynamical quasiparticle scattering by spin and charge fluctuations in Fe-based pnictides within a five-orbital model with on-site interactions. The leading contribution to the scattering rate is calculated from the second-order diagrams with the polarization operator calculated in the random-phase approximation. We find one-particle scattering rates which are highly anisotropic on each Fermi surface sheet due to the momentum dependence of the spin susceptibility and the multi-orbital composition of each Fermi pocket. This fact, combined with the anisotropy of the effective mass, produces disparity between electrons and holes in conductivity, the Hall coefficient, and the Raman initial slope, in qualitative agreement with experimental data.