Project Details
Projekt
Tailoring the electronic structure of epitaxial graphene on SiC (S1)
Applicants
Dr. Kathrin Küster; Professor Dr. Ulrich Starke
Subject Area
Experimental Condensed Matter Physics
Term
since 2021
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 449119662
Graphene exhibits a well-defined two-dimensional electron gas. Functionalization by proximity coupling allows tailoring its electronic properties without interference with the atomic structure of the graphene layer itself. Epitaxial graphene grown on silicon carbide provides a protected interface for such a manipulation. One of the main techniques to functionalize graphene on SiC is intercalation of a thin layer at this interface, which – depending on the intercalated material – can lead to a plenitude of exotic phenomena like extreme doping effects, opening of a band gap, or collective states. At the interface between graphene and SiC, the interlayer can be precisely tuned and new, two-dimensional properties can be created. Besides, epitaxial graphene on SiC allows a technological implementation of such fundamental findings, due to the possibility to grow high quality graphene layers of wafer size on a large band gap semiconductor. This eliminates transfer processes of the graphene onto an insulating substrate, which often deteriorates the quality of the material.In this project we are planning to functionalize the electronic structure of graphene on SiC(0001) by proximity coupling. By intercalation, graphene will be driven into extreme doping regimes to induce correlated states such as charge or spin-density waves or superconductivity. Fine-tuning of the carrier density, e.g., by adsorption will allow scanning different ordered ground states. Tailored interface layers of heavy elements and defined alloy mixtures will induce spin-orbit coupling effects and exotic collective phenomena. Nanostructuring of the graphene and fine tuning of the doping by intercalation will allow the architecture of tailored graphene pn-junctions and pnp-barriers. We plan to utilize the resulting Klein tunneling effect for demonstrating a novel type of transistor device. The electronic and structural properties of the functionalized graphene and the interface layer will be investigated by high resolution and microscopic electron spectroscopy techniques as well as local and non-local transport measurements in collaboration with the project partners within this FOR.
DFG Programme
Research Units
