Nonlocal Response and Anamorphosis: the Case of Few-Layer Black Phosphorus

TL;DR

This paper demonstrates that nonlocal resistance measurements, combined with anamorphosis analysis, provide a highly sensitive method to determine the in-plane anisotropy of few-layer black phosphorus, overcoming limitations of traditional techniques.

Contribution

It introduces a novel approach using nonlocal response and anamorphosis relations to accurately measure transport anisotropy in black phosphorus.

Findings

Nonlocal resistance varies exponentially with anisotropy.

The method can detect anisotropy differences of orders of magnitude.

It offers a new tool for nanoscale transport studies.

Abstract

Few-layer black phosphorus was recently rediscovered as a narrow-bandgap atomically thin semiconductor and has already attracted unprecedented attention due to its interesting properties. One feature of this material that sets it apart from other atomically thin crystals is its structural in-plane anisotropy which manifests in strongly anisotropic transport characteristics. However, traditional angle-resolved conductance measurements present a challenge for nanoscale systems such as black phosphorus, calling for new approaches in precision studies of transport anisotropy. Here we show that the nonlocal response, being exponentially sensitive to the anisotropy value, provides a powerful tool for determining the anisotropy. This is established by combining measurements of the orientation-dependent nonlocal resistance response with the analysis based on the anamorphosis relations. We demonstrate that the nonlocal response can differ by orders of magnitude for different crystallographic directions even when the anisotropy is at most order-one, allowing us to extract accurate anisotropy values.