Disorder effects on transport near AFM quantum phase transitions

TL;DR

This paper examines how disorder influences electrical resistivity near antiferromagnetic quantum critical points, focusing on spin fluctuation scattering and its role in explaining non-Fermi liquid behavior in heavy-fermion materials.

Contribution

It provides a detailed analysis of how anisotropic spin-fluctuation scattering combined with impurity effects accounts for anomalous resistivity temperature dependence.

Findings

Resistivity follows a T^{3/2} dependence in certain regimes.

The interplay of spin fluctuations and disorder explains experimental observations.

Weak impurity scattering significantly affects resistivity behavior.

Abstract

We discuss three different scenarios recently proposed to account for the non-Fermi liquid behavior near antiferromagnetic (AFM) quantum critical points in heavy-Fermion systems: (i) scattering of Fermi liquid quasiparticles by strong spin fluctuations near the spin-density-wave instability, (ii) the breakdown of the Kondo effect due to the competition with the RKKY interaction, and (iii) the formation of magnetic regions due to rare configurations of the disorder. Here we focus on the first scenario and show that it explains in some detail the anomalous temperature dependence of the resistivity observed e.g. in CePd_2Si_2, CeNi_2Ge_2 or CeIn_3. The interplay of strongly anisotropic scattering due to critical spin-fluctuations and weak isotropic impurity scattering leads to a regime with a resistivity rho = rho_0 +Delta rho(T), Delta rho(T) =T^{3/2} f(T/rho_0) \propto T sqrt{rho_0} for sufficiently large T and small rho_0.