Gradient Electronic Landscapes in van der Waals Heterostructures

TL;DR

This paper demonstrates using thermal scanning-probe lithography to create precise, tunable topographic landscapes in van der Waals heterostructures, enabling advanced quantum electronic device architectures.

Contribution

It introduces a novel method to produce smooth, nanoscale topographies in vdW heterostructures, allowing electric-field modulation of charge doping in graphene.

Findings

Successful creation of sinusoidal topographies with nanometer precision

Electrical gating modulates charge-carrier doping via landscape control

Transport measurements show landscape signatures like resistance peaks and oscillations

Abstract

Two-dimensional (2D) materials such as graphene and hexagonal boron nitride (hBN) provide a versatile platform for quantum electronics. Experiments generally require encapsulating graphene within hBN flakes, forming a protective van der Waals (vdW) heterostructure that preserves delicate properties of the embedded crystal. To produce functional devices, heterostructures are typically shaped by electron beam lithography and etching, which has driven progress in 2D materials research. However, patterns are primarily restricted to in-plane geometries such as boxes, holes, and stripes, limiting opportunities for advanced architectures. Here, we use thermal scanning-probe lithography (tSPL) to produce smooth topographic landscapes in vdW heterostructures, controlling the thickness degree of freedom with nanometer precision. We electrically gate a sinusoidal topography to impose an electric-field gradient on the graphene layer to spatially modulate charge-carrier doping. We observe signatures of the landscape in transport measurements-resistance-peak spreading and commensurability oscillations-establishing tSPL for tailoring high-quality quantum electronics.