Ballistic transport in graphene antidot lattices

TL;DR

This paper demonstrates that etching fully encapsulated graphene on hBN preserves high mobility and enables observation of ballistic transport in graphene antidot lattices, bridging classical and quantum regimes.

Contribution

It introduces a gentle etching method for encapsulated graphene that maintains high mobility and reveals ballistic transport in antidot lattices.

Findings

High mobility preserved in etched, encapsulated graphene

Observation of ballistic transport features

Exploration of classical-quantum transport boundary

Abstract

Graphene samples can have a very high carrier mobility if influences from the substrate and the environment are minimized. Embedding a graphene sheet into a heterostructure with hexagonal boron nitride (hBN) on both sides was shown to be a particularly efficient way of achieving a high bulk mobility. Nanopatterning graphene can add extra damage and drastically reduce sample mobility by edge disorder. Preparing etched graphene nanostructures on top of an hBN substrate instead of SiO2 is no remedy, as transport characteristics are still dominated by edge roughness. Here we show that etching fully encapsulated graphene on the nanoscale is more gentle and the high mobility can be preserved. To this end, we prepared graphene antidot lattices where we observe magnetotransport features stemming from ballistic transport. Due to the short lattice period in our samples we can also explore the boundary between the classical and the quantum transport regime.