Heat Transport as a Probe of Electron Scattering by Spin Fluctuations: the Case of Antiferromagnetic CeRhIn5

TL;DR

This study uses heat and charge conduction measurements in CeRhIn5 to investigate how spin fluctuations influence electron scattering, revealing a link between thermal resistivity and magnetic entropy, and identifying a characteristic fluctuation energy scale.

Contribution

It demonstrates that heat transport can probe magnetic fluctuations and introduces T^* as a measure of their energy in an antiferromagnetic heavy-fermion metal.

Findings

Thermal resistivity correlates with magnetic entropy.

The difference between thermal and electrical resistivities peaks at T_N.

T^* is identified as the characteristic energy of magnetic fluctuations.

Abstract

Heat and charge conduction were measured in the heavy-fermion metal CeRhIn5, an antiferromagnet with T_N=3.8 K. The thermal resistivity is found to be proportional to the magnetic entropy, revealing that spin fluctuations are as effective in scattering electrons as they are in disordering local moments. The electrical resistivity, governed by a q^2 weighting of fluctuations, increases monotonically with temperature. In contrast, the difference between thermal and electrical resistivities, characterized by an omega^2 weighting, peaks sharply at T_N and eventually goes to zero at a temperature T^* ~ 8 K. T^* thus emerges as a measure of the characteristic energy of magnetic fluctuations.