Negative Longitudinal Magnetoresistance in the Dirac Semimetal PtSe$_2$ -- Kondo Effect and Surface Spin Dynamics

TL;DR

This study investigates negative longitudinal magnetoresistance in PtSe₂, attributing it to surface Kondo effects caused by Pt-vacancies, with findings supported by experimental transport data and density functional theory.

Contribution

It identifies the Kondo effect from Pt-vacancies as the origin of negative magnetoresistance in PtSe₂, providing an analytical framework and experimental validation.

Findings

Negative magnetoresistance is linked to surface Kondo effect.

Pt-vacancies and sample thickness influence the effect.

Density functional theory supports the vacancy model.

Abstract

The emergence of negative longitudinal magnetoresistance in the topologically non-trivial transition-metal dichalcogenide PtSe$_2$ is studied. Low $T$/high $\mu_0 H$ transport is performed for arbitrary field directions, and an analytical framework is established. The source of the negative longitudinal magnetoresistance is identified as the Kondo effect stemming from Pt-vacancies contributing an uncompensated spin, exclusively at the sample surface. The concentration of vacancies and the sample thickness are identified as tuning parameters. The findings are substantiated by density functional theory, which corroborates the proposed Pt-vacancy model.