Integrated Graphene Nanoconstriction Hall Bar Devices for Magnetotransport Studies in Quantum Confined Structures

We fabricated graphene nanoconstrictions from epitaxial graphene on SiC that exhibit negative magnetoresistance up to -54% at 1.6K. To investigate its possible origins, including the formation of Landau levels in the graphene leads, we developed new gated graphene devices integrating Hall bar leads with a central nanoconstriction. This design enables simultaneous measurement of Hall voltage, carrier density, and the GQD's magnetoresistance within a single device, providing a more complete picture of transport phenomena in graphene nanostructures.