Quantum nanoconstrictions fabricated by cryo-etching in encapsulated graphene

Abstract

More than a decade after the discovery of graphene, ballistic transport in nanostructures based on this intriguing material still represents a challenging field of research in two-dimensional electronics. The presence of rough edges in nanostructures based on this material prevents the appearance of truly ballistic electron transport as theo\-re\-tically predicted and, therefore, not well-developed plateaus of conductance have been revealed to date. In this work we report on a novel implementation of the cryo-etching method, which enabled us to fabricate graphene nanoconstrictions encapsulated between hexagonal boron nitride thin films with unprecedented control of the structure edges. High quality smooth nanometer-rough edges are characterized by atomic force microscopy and a clear correlation between low roughness and the existence of well-developed quantized conductance steps with the concomitant occurrence of ballistic transport is found at low temperature. In par\-ti\-cu\-lar, we come upon exact 2$e^2/h$ quantization steps of conductance at zero magnetic field due to size quantization, as it has been theoretically predicted for truly ballistic electron transport through graphene nanoconstrictions.

References in corpus (15)

• The electronic properties of graphene
• Energy Band Gap Engineering of Graphene Nanoribbons
• Giant Intrinsic Carrier Mobilities in Graphene and Its Bilayer
• Realization of a High Mobility Dual-gated Graphene Field Effect Transistor with Al2O3 Dielectric
• The hot pick-up technique for batch assembly of van der Waals heterostructures
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• Conductance Quantization in Graphene Nanoribbons
• Quantized conductance of a suspended graphene nanoconstriction
• Electrostatically induced quantum point contact in bilayer graphene
• Size quantization of Dirac fermions in graphene constrictions
• From diffusive to ballistic transport in etched graphene constrictions and nanoribbons
• Conductance quantization in graphene nanoconstrictions with mesoscopically smooth but atomically stepped boundaries
• Fabry-Pérot resonances and a crossover to the quantum Hall regime in ballistic graphene quantum point contacts
• Quantized electron transport through graphene nanoconstrictions

Cited by in corpus (7)

• Graphene-based quantum Hall interferometer with self-aligned side gates
• Superballistic conduction in hydrodynamic antidot graphene superlattices
• Scattering of topological kink-antikink states in bilayer graphene structures
• Geometry effects in topologically confined bilayer graphene loops
• Conductance of electrostatic wire junctions in bilayer graphene
• Impact of electron-electron interactions on the thermoelectric efficiency of graphene quantum point contacts
• Electrostatic tuning of bilayer graphene edge modes