Abnormal planar Hall effect and disentanglement of incoherent and coherent transport in a Kondo lattice

TL;DR

This paper investigates the development of coherent heavy-electron states from incoherent localized moments in a Kondo lattice, using planar Hall effect measurements to distinguish different transport contributions.

Contribution

It introduces a novel magneto-transport approach to disentangle incoherent and coherent transport in Kondo lattices, demonstrated on CeCo$_2$Ga$_8$.

Findings

Disentanglement of incoherent and coherent Kondo scattering contributions.

Visualization of a multi-stage development of heavy-electron coherence.

Effective method for studying Kondo lattice coherence via planar Hall effect.

Abstract

The nature of localized-itinerant transition in Kondo lattice systems remains a mystery despite intensive investigations in past decades. While it is often identified from the coherent peak in magnetic resistivity, recent angle-resolved photoemission spectroscopy and ultrafast optical spectroscopy revealed a precursor incoherent region with band bending and hybridization fluctuations. This raises the question of how the coherent heavy-electron state is developed from an incoherent background of fluctuating localized moments and then established at sufficiently low temperatures. Here, on the example of the quasi-one-dimensional Kondo lattice compound CeCo$_2$Ga$_8$, we show that planar Hall effect and planar anisotropic magnetoresistance measurements provide an effective way to disentangle the incoherent Kondo scattering contribution and the coherent heavy-electron contribution, and a multi-stage process is directly visualized with lowering temperature by their distinct angle-dependent patterns in magneto-transport. Our idea may be extended to other measurements and thereby opens up a pathway for systematically investigating the fundamental physics of Kondo lattice coherence.