Effects of Lifshitz Transition on Charge Transport in Magnetic Phases of Fe-Based Superconductors

TL;DR

This paper investigates how Lifshitz transitions influence charge transport and resistivity anisotropy in Fe-based superconductors, linking Fermi surface changes to magnetic and nematic effects.

Contribution

It demonstrates that Lifshitz transitions caused by magnetic ordering significantly impact resistivity behavior and anisotropy in Fe-based superconductors.

Findings

Resistivity drops sharply below the N{\'e}el temperature due to Lifshitz transition.

Resistivity anisotropy is affected by Lifshitz transition and nematic defect structures.

Impurity scattering within a two-band model explains temperature dependence of resistivity.

Abstract

The unusual temperature dependence of the resistivity and its in-plane anisotropy observed in the Fe-based superconducting materials, particularly Ba(Fe$_{1-x}$Co$_x$)$_2$As$_2$, has been a longstanding puzzle. Here we consider the effect of impurity scattering on the temperature dependence of the average resistivity within a simple two-band model of a dirty spin density wave metal. The sharp drop in resistivity below the N\'eel temperature $T_N$ in the parent compound can only be understood in terms of a Lifshitz transition following Fermi surface reconstruction upon magnetic ordering. We show that the observed resistivity anisotropy in this phase, arising from nematic defect structures, is affected by the Lifshitz transition as well.