Role of spin fluctuations in anomalous transport of MnAlGe

Determine how finite-temperature spin fluctuations modify the intrinsic and extrinsic contributions to anomalous Hall and anomalous Nernst transport in MnAlGe.

Background

The experimentally measured anomalous Hall and anomalous Nernst magnitudes are substantially lower than zero-temperature theoretical predictions. The paper attributes this suppression partly to thermally induced spin fluctuations and electron–magnon scattering, which are enhanced in quasi-two-dimensional ferromagnets. Although the calculations and composition trends suggest that spin fluctuations primarily reduce the intrinsic Berry-curvature contribution, the paper states that their detailed effect on intrinsic versus extrinsic anomalous transport remains unresolved.