Engineering high quality graphene superlattices via ion milled ultra-thin etching masks

Abstract

Nanofabrication research pursues the miniaturization of patterned feature size. In the current state of the art, micron scale areas can be patterned with features down to ~ 30 nm pitch using electron beam lithography. Our work demonstrates a new nanofabrication technique which allows patterning periodic structures with a pitch down to 16 nm. It is based on focused ion beam milling of suspended membranes, with minimal proximity effects typical to electron beam lithography. The membranes are then transferred and used as hard etching masks. We benchmark our technique by engineering a superlattice potential in single layer graphene using a thin graphite patterned gate electrode. Our electronic transport characterization shows high quality superlattice properties and a rich Hofstadter butterfly spectrum. Our technique opens the path towards the realization of very short period superlattices in 2D materials, comparable to those in natural moire systems, but with the ability to control lattice symmetries and strength. This can pave the way for a versatile solid-state quantum simulator platform and the study of correlated electron phases.

References in corpus (10)

• Defect scattering in graphene
• 2D Materials for Future Heterogeneous Electronics
• New Generation of Massless Dirac Fermions in Graphene under External Periodic Potentials
• Superlattice-induced insulating states and valley-protected orbits in twisted bilayer graphene
• Landau Levels and Quantum Hall Effect in Graphene Superlattices
• High-temperature quantum oscillations caused by recurring Bloch states in graphene superlattices
• Quantum simulation of Fermi-Hubbard models in semiconductor quantum dot arrays
• Topological and stacked flat bands in bilayer graphene with a superlattice potential
• Patterned bilayer graphene as a tunable, strongly correlated system
• Materials and devices for fundamental quantum science and quantum technologies

Cited by in corpus (21)

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• Chiral model of twisted bilayer graphene realized in a monolayer
• Designing topology and fractionalization in narrow gap semiconductor films via electrostatic engineering
• Charge Conservation Beyond Uniformity: Spatially Inhomogeneous Electromagnetic Response in Periodic Solids
• Efficient prediction of superlattice and anomalous miniband topology from quantum geometry
• Probing miniband structure and Hofstadter butterfly in gated graphene superlattices via magnetotransport
• Piezoelectric Electrostatic Superlattices in Monolayer MoS${}_2$
• Inducing topological flat bands in bilayer graphene with electric and magnetic superlattices
• Tunable Nanophotonic Devices and Cavities based on a Two-Dimensional Magnet
• Designing Band Structures by Patterned Dielectric Superlattices
• Understanding Disorder in Monolayer Graphene Devices with Gate-Defined Superlattices
• Giant Shift Current in Electrically-Tunable Superlattice Bilayer Graphene
• Lithography defined semiconductor moires with anomalous in-gap quantum Hall states
• Enhanced Backgate Tunability on Interfacial Carrier Concentration in Ionic Liquid-Gated MoS2 Devices
• Designing Flat Bands and Pseudo-Landau Levels in GaAs with Patterned Gates
• Efficient prediction of topological superlattice bands with spin-orbit coupling
• Magnetic Bloch bands and Weiss oscillations in Dirac mass superlattices