Connecting the Dots: Scalability and Connectivity of Bilayer Graphene Quantum Dots for Future Quantum Technologies

• Applicant: Dr. Angelika Hildegard Knothe-Schulz
• Subject Area: Theoretical Condensed Matter Physics
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 529637137

Electrostatically induced nanostructures in bilayer graphene are promising for quantum technologies, e.g., quantum dots as spin and valley qubits. Over the last few years, my collaborators and I have provided the groundwork for understanding single, isolated electrically defined nanostructures, such as quantum wires, quantum dots, and all-electronic cavities in bilayer graphene. The proposed research will contribute the necessary theoretical work on coupling between quantum dots in setups with multiple bilayer graphene quantum dots as a step towards future scalable, modular quantum dot architectures. We will study different dot-dot coupling mechanisms across different length scales: 1. Short-range coupling between two bilayer graphene quantum dots and in small-scale lattices of quantum dots; 2. The coupling between all-electronic, gate-defined bilayer graphene cavities and bilayer graphene quantum dots; 3. Long-range coupling between bilayer graphene quantum dots mediated by electronic bilayer graphene cavities; Bilayer graphene yields outstandingly high-quality devices where the unique materials’ properties and the electrostatic confinement are fully tunable by the external gates, which allows for combining distinct functionalities and operating in diverse regimes. Coupling different gate-induced nanostructures in one and the same material will be favourable for small-scale, fully integrated, single-crystal design. Thanks to the rapid experimental progress on gate-defined bilayer graphene nanostructures, such advanced nanostructure designs are now within reach. Hence, there is a need for innovative ideas and well-founded theoretical predictions on how to make these bilayer graphene nanostructures useful in today’s and tomorrow’s applications. Here, the research of this proposal will contribute by advancing the theoretical understanding of coupled bilayer graphene quantum dots and hybrid, all-electronic dot-cavity systems, thereby pushing forward the field of bilayer graphene-based nanostructures for future quantum technologies. By targeting coupled bilayer graphene-based nanostructures for quantum technologies, this research of this proposal will yield new physics of nano-scale quantum systems in low-dimensional materials, hybrid setups, and many-body states with different degrees of freedom, and will pave the way for new applications using these nanostructures as building blocks for modular quantum networks.

• DFG Programme: Research Grants