Hall effect and resistivity study of the magnetic transition, carrier content and Fermi liquid behavior in Ba(Fe(1-x) Cox)2As2

TL;DR

This study investigates the electronic transport, magnetic transition, and Fermi liquid behavior in Ba(Fe(1-x)Cox)2As2, revealing electron dominance, band structure changes at low doping, and Fermi liquid characteristics at higher doping levels.

Contribution

It provides new insights into how doping affects carrier concentration, band structure, and scattering mechanisms in Ba(Fe(1-x)Cox)2As2, especially before and after superconductivity emerges.

Findings

Electron carriers dominate transport across the phase diagram.

Band structure changes occur at doping levels below 2%.

Fermi liquid behavior is observed at higher doping with T^2 scattering law.

Abstract

The negative Hall constant R_H measured all over the phase diagram of Ba(Fe(1-x)Cox)2As2 allows us to show that electron carriers always dominate the transport properties. The evolution of R_H with x at low doping (x<2%) indicates that important band structure changes happen for x<2% prior to the emergence of superconductivity. For higher x, an change of the electron concentration with T is required to explain the low T variations of R_H, while the electron scattering rate displays the T^2 law expected for a Fermi liquid. The T=0 residual scattering is affected by Co disorder in the magnetic phase, but is rather dominated by incipient disorder in the paramagnetic state.