Direct Observation of Long-range field-effect from gate tuning of non-local conductivity

TL;DR

This paper demonstrates a long-range field-effect in WTe₂ devices, where gate tuning influences bulk transport properties beyond the electrostatic screening length, due to non-local transport effects and surface scattering.

Contribution

It reveals a novel long-range field-effect mechanism in thick WTe₂ devices driven by surface scattering and non-local transport, supported by theoretical modeling.

Findings

Gate-induced changes in transport properties in thick WTe₂

Reproduction of magneto-transport dependence through theory

Surface scattering modulates bulk carrier mobility

Abstract

We report the observation of an unexpected, long-range field-effect in WTe$_2$ devices, leading to large gate-induced changes of the transport properties of crystals much thicker than the electrostatic screening length. The phenomenon --which manifests itself very differently from the conventional field-effect-- originates from the non-local nature of transport in the devices that are thinner than the carrier mean free path, because of the dominant role of surface scattering. We reproduce theoretically the gate dependence of the measured classical and quantum magneto-transport in all detail, and show that the phenomenon is caused by the gate-tuning of the bulk carrier mobility by changing the scattering at the surface. Our results demonstrate the possibility to gate tune the electronic properties deep in the interior of conducting materials, avoiding limitations imposed by electrostatic screening.