Electronic, Optical, and Transport Properties of Quantum Dots in Proximitised Bilayer Graphene

• Applicant: Dr. Angelika Hildegard Knothe-Schulz
• Subject Area: Theoretical Condensed Matter Physics
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 555830897

We propose to study the interplay between wave function confinement and proximity effects in quantum dots in heterostructures of bilayer graphene (BLG) proximitised with other 2D materials, such as transition metal dichalcogenides (TMDs) and 2D magnets. Gate-defined quantum dots in gapped BLG have proven to be an exciting platform to study their confined few-particle states and as hosts for potential quantum information technologies, such as qubits. By virtue of the proximity effect, TMDs and magnetic materials will endow the confined states with additional characteristics, such as strong spin-orbit coupling and magnetic exchange fields, not present in the BLG itself. While proximity effects have been studied experimentally and theoretically in extended systems before, the physics of proximity coupling in confined systems is much less explored. Gate-defined quantum dots in proximitised BLG heterostructures uniquely combine controllable quantum confinement, intrinsic, and proximity-induced material properties. These dots hence represent an ideal testbed to investigate the interplay of confinement, proximity, and interaction effects. First electrostatically defined nanostructures in proximitised BLG are only now being experimentally realised. This project will develop the first theoretical understanding of proximity effects in confined geometries studying quantum dots in proximitised BLG. We will develop realistic microscopic models of the dots capturing BLG’s material characteristics, the proximity-induced features, few-electron interactions, and the properties of the confinement. We will study the confined states of single- and coupled multi-dot systems, their optical and transport properties, as well as how tunable proximity effects in confined geometries may be used to design proximity-tailored quantum dots, e.g., for their use as qubits.

• DFG Programme: Research Grants