# Anomalous Nonlocal Resistance and Spin-charge Conversion Mechanisms in Two-Dimensional Metals

## TL;DR

This paper reveals unusual nonlocal resistance behaviors in 2D metals with spin-orbit coupling, including negative resistance and asymmetric Hanle oscillations, due to direct magnetoelectric coupling, advancing understanding of spin-charge conversion.

## Contribution

It introduces a new theoretical framework accounting for direct magnetoelectric coupling in nonlocal transport, explaining anomalous resistance features in 2D metals.

## Key findings

- Nonlocal resistance can be negative and oscillate with distance.
- Oscillations under magnetic field can be asymmetric under field reversal.
- Effects are observable in adatom-functionalized graphene.

## Abstract

We uncover two anomalous features in the nonlocal transport behavior of two-dimensional metallic materials with spin-orbit coupling. Firstly, the nonlocal resistance can have negative values and oscillate with distance, even in the absence of a magnetic field. Secondly, the oscillations of the nonlocal resistance under an applied in-plane magnetic field (Hanle effect) can be asymmetric under field reversal. Both features are produced by direct magnetoelectric coupling, which is possible in materials with broken inversion symmetry but was not included in previous spin diffusion theories of nonlocal transport. These effects can be used to identify the relative contributions of different spin-charge conversion mechanisms. They should be observable in adatom-functionalized graphene, and may provide the reason for discrepancies in recent nonlocal transport experiments on graphene.