Weak magnetoresistance of disordered heavy fermion systems

TL;DR

This paper investigates the weak negative magnetoresistance in disordered heavy fermion systems, comparing experimental results with theoretical calculations based on a disordered Anderson model, revealing contrasting field dependencies in thermodynamic and transport properties.

Contribution

It introduces a phenomenological spectral function approach within the disordered Anderson model to explain weak magnetoresistance in heavy fermion systems, supported by experimental and theoretical comparison.

Findings

Both experiment and theory show weak negative magnetoresistance.

Thermodynamic quantities exhibit strong field dependence.

Distributions of Kondo scales explain differing field responses.

Abstract

We compare the magnetoresistance of UCu$_{3.5}$Pd$_{1.5}$ with calculations done within the disordered heavy fermion framework of Miranda et al. using a phenomenological spectral function for the Anderson model, calibrated against Bethe ansatz and quantum Monte Carlo results. Both in experiment and theory, we find a weak negative magnetoresistance. In contrast, thermodynamic quantities have a strong field dependence. Using qualitative arguments broad distribution of Kondo scales, we explain the different field dependence of susceptibility and resistivity.